class IO
Expect library adds the IO instance method expect, which does similar act to tcl's expect extension.
In order to use this method, you must require expect:
require 'expect'
Please see expect for usage.
The IO class is the basis for all input and output in Ruby. An I/O stream may be duplexed (that is, bidirectional), and so may use more than one native operating system stream.
Many of the examples in this section use the File class, the only standard subclass of IO. The two classes are closely associated. Like the File class, the Socket library subclasses from IO (such as TCPSocket or UDPSocket).
The Kernel#open method can create an IO (or File) object for these types of arguments:
-
A plain string represents a filename suitable for the underlying operating system.
-
A string starting with
"|"indicates a subprocess. The remainder of the string following the"|"is invoked as a process with appropriate input/output channels connected to it. -
A string equal to
"|-"will create another Ruby instance as a subprocess.
The IO may be opened with different file modes (read-only, write-only) and encodings for proper conversion. See ::new for these options. See Kernel#open for details of the various command formats described above.
::popen, the Open3 library, or Process#spawn may also be used to communicate with subprocesses through an IO.
Ruby will convert pathnames between different operating system conventions
if possible. For instance, on a Windows system the filename
"/gumby/ruby/test.rb" will be opened as
"\gumby\ruby\test.rb". When specifying a
Windows-style filename in a Ruby string, remember to escape the
backslashes:
"c:\\gumby\\ruby\\test.rb"
Our examples here will use the Unix-style forward slashes; File::ALT_SEPARATOR can be used to get the platform-specific separator character.
The global constant ARGF (also accessible as $<) provides an IO-like stream which allows access to all files mentioned on the command line (or STDIN if no files are mentioned). ARGF#path and its alias ARGF#filename are provided to access the name of the file currently being read.
io/console¶ ↑
The io/console extension provides methods for interacting with the console. The console can be accessed from ::console or the standard input/output/error IO objects.
Requiring io/console adds the following methods:
Example:
require 'io/console' rows, columns = $stdin.winsize puts "Your screen is #{columns} wide and #{rows} tall"
Constants
- SEEK_CUR
- SEEK_END
- SEEK_SET
Public Class Methods
Opens the file, optionally seeks to the given offset, then returns
length bytes (defaulting to the rest of the file).
binread ensures the file is closed before returning. The open
mode would be “rb:ASCII-8BIT”.
IO.binread("testfile") #=> "This is line one\nThis is line two\nThis is line three\nAnd so on...\n" IO.binread("testfile", 20) #=> "This is line one\nThi" IO.binread("testfile", 20, 10) #=> "ne one\nThis is line "
static VALUE
rb_io_s_binread(int argc, VALUE *argv, VALUE io)
{
VALUE offset;
struct foreach_arg arg;
rb_scan_args(argc, argv, "12", NULL, NULL, &offset);
FilePathValue(argv[0]);
arg.io = rb_io_open(argv[0], rb_str_new_cstr("rb:ASCII-8BIT"), Qnil, Qnil);
if (NIL_P(arg.io)) return Qnil;
arg.argv = argv+1;
arg.argc = (argc > 1) ? 1 : 0;
if (!NIL_P(offset)) {
rb_io_seek(arg.io, offset, SEEK_SET);
}
return rb_ensure(io_s_read, (VALUE)&arg, rb_io_close, arg.io);
}
Same as IO.write except opening the file in binary mode and
ASCII-8BIT encoding (“wb:ASCII-8BIT”).
static VALUE
rb_io_s_binwrite(int argc, VALUE *argv, VALUE io)
{
return io_s_write(argc, argv, 1);
}
Returns an File instance opened console.
You must require 'io/console' to use this method.
static VALUE
console_dev(VALUE klass)
{
VALUE con = 0;
rb_io_t *fptr;
if (klass == rb_cIO) klass = rb_cFile;
if (rb_const_defined(klass, id_console)) {
con = rb_const_get(klass, id_console);
if (RB_TYPE_P(con, T_FILE)) {
if ((fptr = RFILE(con)->fptr) && GetReadFD(fptr) != -1)
return con;
}
rb_mod_remove_const(klass, ID2SYM(id_console));
}
{
VALUE args[2];
#if defined HAVE_TERMIOS_H || defined HAVE_TERMIO_H || defined HAVE_SGTTY_H
# define CONSOLE_DEVICE "/dev/tty"
#elif defined _WIN32
# define CONSOLE_DEVICE "con$"
# define CONSOLE_DEVICE_FOR_READING "conin$"
# define CONSOLE_DEVICE_FOR_WRITING "conout$"
#endif
#ifndef CONSOLE_DEVICE_FOR_READING
# define CONSOLE_DEVICE_FOR_READING CONSOLE_DEVICE
#endif
#ifdef CONSOLE_DEVICE_FOR_WRITING
VALUE out;
rb_io_t *ofptr;
#endif
int fd;
#ifdef CONSOLE_DEVICE_FOR_WRITING
fd = rb_cloexec_open(CONSOLE_DEVICE_FOR_WRITING, O_RDWR, 0);
if (fd < 0) return Qnil;
rb_update_max_fd(fd);
args[1] = INT2FIX(O_WRONLY);
args[0] = INT2NUM(fd);
out = rb_class_new_instance(2, args, klass);
#endif
fd = rb_cloexec_open(CONSOLE_DEVICE_FOR_READING, O_RDWR, 0);
if (fd < 0) {
#ifdef CONSOLE_DEVICE_FOR_WRITING
rb_io_close(out);
#endif
return Qnil;
}
rb_update_max_fd(fd);
args[1] = INT2FIX(O_RDWR);
args[0] = INT2NUM(fd);
con = rb_class_new_instance(2, args, klass);
GetOpenFile(con, fptr);
fptr->pathv = rb_obj_freeze(rb_str_new2(CONSOLE_DEVICE));
#ifdef CONSOLE_DEVICE_FOR_WRITING
GetOpenFile(out, ofptr);
# ifdef HAVE_RB_IO_GET_WRITE_IO
ofptr->pathv = fptr->pathv;
fptr->tied_io_for_writing = out;
# else
fptr->f2 = ofptr->f;
ofptr->f = 0;
# endif
ofptr->mode |= FMODE_SYNC;
#endif
fptr->mode |= FMODE_SYNC;
rb_const_set(klass, id_console, con);
}
return con;
}
::copy_stream copies src to dst. src and dst is either a filename or an IO.
This method returns the number of bytes copied.
If optional arguments are not given, the start position of the copy is the beginning of the filename or the current file offset of the IO. The end position of the copy is the end of file.
If copy_length is given, No more than copy_length bytes are copied.
If src_offset is given, it specifies the start position of the copy.
When src_offset is specified and src is an IO, ::copy_stream doesn't move the current file offset.
static VALUE
rb_io_s_copy_stream(int argc, VALUE *argv, VALUE io)
{
VALUE src, dst, length, src_offset;
struct copy_stream_struct st;
MEMZERO(&st, struct copy_stream_struct, 1);
rb_scan_args(argc, argv, "22", &src, &dst, &length, &src_offset);
st.src = src;
st.dst = dst;
if (NIL_P(length))
st.copy_length = (off_t)-1;
else
st.copy_length = NUM2OFFT(length);
if (NIL_P(src_offset))
st.src_offset = (off_t)-1;
else
st.src_offset = NUM2OFFT(src_offset);
rb_fd_init(&st.fds);
rb_ensure(copy_stream_body, (VALUE)&st, copy_stream_finalize, (VALUE)&st);
return OFFT2NUM(st.total);
}
Synonym for IO.new.
static VALUE
rb_io_s_for_fd(int argc, VALUE *argv, VALUE klass)
{
VALUE io = rb_obj_alloc(klass);
rb_io_initialize(argc, argv, io);
return io;
}
Executes the block for every line in the named I/O port, where lines are separated by sep.
If no block is given, an enumerator is returned instead.
IO.foreach("testfile") {|x| print "GOT ", x }
produces:
GOT This is line one GOT This is line two GOT This is line three GOT And so on...
If the last argument is a hash, it's the keyword argument to open. See
IO.read for detail.
static VALUE
rb_io_s_foreach(int argc, VALUE *argv, VALUE self)
{
VALUE opt;
int orig_argc = argc;
struct foreach_arg arg;
argc = rb_scan_args(argc, argv, "13:", NULL, NULL, NULL, NULL, &opt);
RETURN_ENUMERATOR(self, orig_argc, argv);
open_key_args(argc, argv, opt, &arg);
if (NIL_P(arg.io)) return Qnil;
return rb_ensure(io_s_foreach, (VALUE)&arg, rb_io_close, arg.io);
}
Returns a new IO object (a stream) for the given
integer file descriptor fd and mode string.
opt may be used to specify parts of mode in a
more readable fashion. See also ::sysopen and ::for_fd.
::new is called by various File and IO opening methods such as ::open, Kernel#open, and File.open.
Open Mode¶ ↑
When mode is an integer it must be combination of the modes
defined in File::Constants
(File::RDONLY, +File::WRONLY | File::CREAT+). See the open(2)
man page for more information.
When mode is a string it must be in one of the following
forms:
fmode fmode ":" ext_enc fmode ":" ext_enc ":" int_enc fmode ":" "BOM|UTF-*"
fmode is an IO open mode string,
ext_enc is the external encoding for the IO and int_enc is the internal encoding.
IO Open Mode¶ ↑
Ruby allows the following open modes:
"r" Read-only, starts at beginning of file (default mode).
"r+" Read-write, starts at beginning of file.
"w" Write-only, truncates existing file
to zero length or creates a new file for writing.
"w+" Read-write, truncates existing file to zero length
or creates a new file for reading and writing.
"a" Write-only, each write call appends data at end of file.
Creates a new file for writing if file does not exist.
"a+" Read-write, each write call appends data at end of file.
Creates a new file for reading and writing if file does
not exist.
The following modes must be used separately, and along with one or more of the modes seen above.
"b" Binary file mode
Suppresses EOL <-> CRLF conversion on Windows. And
sets external encoding to ASCII-8BIT unless explicitly
specified.
"t" Text file mode
When the open mode of original IO is read only, the mode cannot be changed to be writable. Similarly, the open mode cannot be changed from write only to readable.
When such a change is attempted the error is raised in different locations according to the platform.
IO Encoding¶ ↑
When ext_enc is specified, strings read will be tagged by the
encoding when reading, and strings output will be converted to the
specified encoding when writing.
When ext_enc and int_enc are specified read
strings will be converted from ext_enc to int_enc
upon input, and written strings will be converted from int_enc
to ext_enc upon output. See Encoding for further details of transcoding on
input and output.
If “BOM|UTF-8”, “BOM|UTF-16LE” or “BOM|UTF16-BE” are used, ruby checks for
a Unicode BOM in the input document to help determine the encoding. For
UTF-16 encodings the file open mode must be binary. When present, the BOM
is stripped and the external encoding from the BOM is used. When the BOM
is missing the given Unicode encoding is used as ext_enc.
(The BOM-set encoding option is case insensitive, so “bom|utf-8” is also
valid.)
Options¶ ↑
opt can be used instead of mode for improved
readability. The following keys are supported:
- :mode
-
Same as
modeparameter - :external_encoding
-
External encoding for the IO. “-” is a synonym for the default external encoding.
- :internal_encoding
-
Internal encoding for the IO. “-” is a synonym for the default internal encoding.
If the value is nil no conversion occurs.
- :encoding
-
Specifies external and internal encodings as “extern:intern”.
- :textmode
-
If the value is truth value, same as “t” in argument
mode. - :binmode
-
If the value is truth value, same as “b” in argument
mode. - :autoclose
-
If the value is
false, thefdwill be kept open after this IO instance gets finalized.
Also, opt can have same keys in String#encode for controlling
conversion between the external encoding and the internal encoding.
Example 1¶ ↑
fd = IO.sysopen("/dev/tty", "w") a = IO.new(fd,"w") $stderr.puts "Hello" a.puts "World"
Produces:
Hello World
Example 2¶ ↑
require 'fcntl' fd = STDERR.fcntl(Fcntl::F_DUPFD) io = IO.new(fd, mode: 'w:UTF-16LE', cr_newline: true) io.puts "Hello, World!" fd = STDERR.fcntl(Fcntl::F_DUPFD) io = IO.new(fd, mode: 'w', cr_newline: true, external_encoding: Encoding::UTF_16LE) io.puts "Hello, World!"
Both of above print “Hello, World!” in UTF-16LE to standard error output
with converting EOL generated by puts to CR.
static VALUE
rb_io_initialize(int argc, VALUE *argv, VALUE io)
{
VALUE fnum, vmode;
rb_io_t *fp;
int fd, fmode, oflags = O_RDONLY;
convconfig_t convconfig;
VALUE opt;
#if defined(HAVE_FCNTL) && defined(F_GETFL)
int ofmode;
#else
struct stat st;
#endif
rb_secure(4);
argc = rb_scan_args(argc, argv, "11:", &fnum, &vmode, &opt);
rb_io_extract_modeenc(&vmode, 0, opt, &oflags, &fmode, &convconfig);
fd = NUM2INT(fnum);
if (rb_reserved_fd_p(fd)) {
rb_raise(rb_eArgError, "The given fd is not accessible because RubyVM reserves it");
}
#if defined(HAVE_FCNTL) && defined(F_GETFL)
oflags = fcntl(fd, F_GETFL);
if (oflags == -1) rb_sys_fail(0);
#else
if (fstat(fd, &st) == -1) rb_sys_fail(0);
#endif
rb_update_max_fd(fd);
#if defined(HAVE_FCNTL) && defined(F_GETFL)
ofmode = rb_io_oflags_fmode(oflags);
if (NIL_P(vmode)) {
fmode = ofmode;
}
else if ((~ofmode & fmode) & FMODE_READWRITE) {
VALUE error = INT2FIX(EINVAL);
rb_exc_raise(rb_class_new_instance(1, &error, rb_eSystemCallError));
}
#endif
if (!NIL_P(opt) && rb_hash_aref(opt, sym_autoclose) == Qfalse) {
fmode |= FMODE_PREP;
}
MakeOpenFile(io, fp);
fp->fd = fd;
fp->mode = fmode;
fp->encs = convconfig;
clear_codeconv(fp);
io_check_tty(fp);
if (fileno(stdin) == fd)
fp->stdio_file = stdin;
else if (fileno(stdout) == fd)
fp->stdio_file = stdout;
else if (fileno(stderr) == fd)
fp->stdio_file = stderr;
if (fmode & FMODE_SETENC_BY_BOM) io_set_encoding_by_bom(io);
return io;
}
With no associated block, IO.open is a synonym for ::new. If the optional code block is
given, it will be passed io as an argument, and the IO object will automatically be closed when the block
terminates. In this instance, ::open
returns the value of the block.
See ::new for a description of the
fd, mode and opt parameters.
static VALUE
rb_io_s_open(int argc, VALUE *argv, VALUE klass)
{
VALUE io = rb_class_new_instance(argc, argv, klass);
if (rb_block_given_p()) {
return rb_ensure(rb_yield, io, io_close, io);
}
return io;
}
Creates a pair of pipe endpoints (connected to each other) and returns them
as a two-element array of IO objects: [
read_io, write_io ].
If a block is given, the block is called and returns the value of the block. read_io and write_io are sent to the block as arguments. If read_io and write_io are not closed when the block exits, they are closed. i.e. closing read_io and/or write_io doesn't cause an error.
Not available on all platforms.
If an encoding (encoding name or encoding object) is specified as an optional argument, read string from pipe is tagged with the encoding specified. If the argument is a colon separated two encoding names “A:B”, the read string is converted from encoding A (external encoding) to encoding B (internal encoding), then tagged with B. If two optional arguments are specified, those must be encoding objects or encoding names, and the first one is the external encoding, and the second one is the internal encoding. If the external encoding and the internal encoding is specified, optional hash argument specify the conversion option.
In the example below, the two processes close the ends of the pipe that
they are not using. This is not just a cosmetic nicety. The read end of a
pipe will not generate an end of file condition if there are any writers
with the pipe still open. In the case of the parent process, the
rd.read will never return if it does not first issue a
wr.close.
rd, wr = IO.pipe if fork wr.close puts "Parent got: <#{rd.read}>" rd.close Process.wait else rd.close puts "Sending message to parent" wr.write "Hi Dad" wr.close end
produces:
Sending message to parent Parent got: <Hi Dad>
static VALUE
rb_io_s_pipe(int argc, VALUE *argv, VALUE klass)
{
int pipes[2], state;
VALUE r, w, args[3], v1, v2;
VALUE opt;
rb_io_t *fptr, *fptr2;
int fmode = 0;
VALUE ret;
argc = rb_scan_args(argc, argv, "02:", &v1, &v2, &opt);
if (rb_pipe(pipes) == -1)
rb_sys_fail(0);
args[0] = klass;
args[1] = INT2NUM(pipes[0]);
args[2] = INT2FIX(O_RDONLY);
r = rb_protect(io_new_instance, (VALUE)args, &state);
if (state) {
close(pipes[0]);
close(pipes[1]);
rb_jump_tag(state);
}
GetOpenFile(r, fptr);
io_encoding_set(fptr, v1, v2, opt);
args[1] = INT2NUM(pipes[1]);
args[2] = INT2FIX(O_WRONLY);
w = rb_protect(io_new_instance, (VALUE)args, &state);
if (state) {
close(pipes[1]);
if (!NIL_P(r)) rb_io_close(r);
rb_jump_tag(state);
}
GetOpenFile(w, fptr2);
rb_io_synchronized(fptr2);
extract_binmode(opt, &fmode);
#if DEFAULT_TEXTMODE
if ((fptr->mode & FMODE_TEXTMODE) && (fmode & FMODE_BINMODE)) {
fptr->mode &= ~FMODE_TEXTMODE;
setmode(fptr->fd, O_BINARY);
}
#if defined(RUBY_TEST_CRLF_ENVIRONMENT) || defined(_WIN32)
if (fptr->encs.ecflags & ECONV_DEFAULT_NEWLINE_DECORATOR) {
fptr->encs.ecflags |= ECONV_UNIVERSAL_NEWLINE_DECORATOR;
}
#endif
#endif
fptr->mode |= fmode;
#if DEFAULT_TEXTMODE
if ((fptr2->mode & FMODE_TEXTMODE) && (fmode & FMODE_BINMODE)) {
fptr2->mode &= ~FMODE_TEXTMODE;
setmode(fptr2->fd, O_BINARY);
}
#endif
fptr2->mode |= fmode;
ret = rb_assoc_new(r, w);
if (rb_block_given_p()) {
VALUE rw[2];
rw[0] = r;
rw[1] = w;
return rb_ensure(rb_yield, ret, pipe_pair_close, (VALUE)rw);
}
return ret;
}
Runs the specified command as a subprocess; the subprocess's standard
input and output will be connected to the returned IO object.
The PID of the started process can be obtained by #pid method.
cmd is a string or an array as follows.
cmd: "-" : fork commandline : command line string which is passed to a shell [env, cmdname, arg1, ..., opts] : command name and zero or more arguments (no shell) [env, [cmdname, argv0], arg1, ..., opts] : command name, argv[0] and zero or more arguments (no shell) (env and opts are optional.)
If cmd is a String “-'', then a
new instance of Ruby is started as the subprocess.
If cmd is an Array of String, then it
will be used as the subprocess's argv bypassing a shell.
The array can contains a hash at first for environments and a hash at last
for options similar to spawn.
The default mode for the new file object is “r'', but mode may be set to any of the modes listed in the description for class IO. The last argument opt qualifies mode.
# set IO encoding IO.popen("nkf -e filename", :external_encoding=>"EUC-JP") {|nkf_io| euc_jp_string = nkf_io.read } # merge standard output and standard error using # spawn option. See the document of Kernel.spawn. IO.popen(["ls", "/", :err=>[:child, :out]]) {|ls_io| ls_result_with_error = ls_io.read } # spawn options can be mixed with IO options IO.popen(["ls", "/"], :err=>[:child, :out]) {|ls_io| ls_result_with_error = ls_io.read }
Raises exceptions which IO.pipe and Kernel.spawn
raise.
If a block is given, Ruby will run the command as a child connected to Ruby
with a pipe. Ruby's end of the pipe will be passed as a parameter to
the block. At the end of block, Ruby close the pipe and sets
$?. In this case IO.popen returns the value of
the block.
If a block is given with a cmd of “-'', the
block will be run in two separate processes: once in the parent, and once
in a child. The parent process will be passed the pipe object as a
parameter to the block, the child version of the block will be passed
nil, and the child's standard in and standard out will be
connected to the parent through the pipe. Not available on all platforms.
f = IO.popen("uname") p f.readlines f.close puts "Parent is #{Process.pid}" IO.popen("date") { |f| puts f.gets } IO.popen("-") {|f| $stderr.puts "#{Process.pid} is here, f is #{f.inspect}"} p $? IO.popen(%w"sed -e s|^|<foo>| -e s&$&;zot;&", "r+") {|f| f.puts "bar"; f.close_write; puts f.gets }
produces:
["Linux\n"] Parent is 21346 Thu Jan 15 22:41:19 JST 2009 21346 is here, f is #<IO:fd 3> 21352 is here, f is nil #<Process::Status: pid 21352 exit 0> <foo>bar;zot;
static VALUE
rb_io_s_popen(int argc, VALUE *argv, VALUE klass)
{
const char *modestr;
VALUE pname, pmode = Qnil, port, tmp, opt = Qnil, env = Qnil, execarg_obj = Qnil;
int oflags, fmode;
convconfig_t convconfig;
if (argc > 1 && !NIL_P(opt = rb_check_hash_type(argv[argc-1]))) --argc;
if (argc > 1 && !NIL_P(env = rb_check_hash_type(argv[0]))) --argc, ++argv;
switch (argc) {
case 2:
pmode = argv[1];
case 1:
pname = argv[0];
break;
default:
{
int ex = !NIL_P(opt);
rb_error_arity(argc + ex, 1 + ex, 2 + ex);
}
}
tmp = rb_check_array_type(pname);
if (!NIL_P(tmp)) {
long len = RARRAY_LEN(tmp);
#if SIZEOF_LONG > SIZEOF_INT
if (len > INT_MAX) {
rb_raise(rb_eArgError, "too many arguments");
}
#endif
tmp = rb_ary_dup(tmp);
RBASIC(tmp)->klass = 0;
execarg_obj = rb_execarg_new((int)len, RARRAY_PTR(tmp), FALSE);
rb_ary_clear(tmp);
}
else {
SafeStringValue(pname);
execarg_obj = Qnil;
if (!is_popen_fork(pname))
execarg_obj = rb_execarg_new(1, &pname, TRUE);
}
if (!NIL_P(execarg_obj)) {
if (!NIL_P(opt))
opt = rb_execarg_extract_options(execarg_obj, opt);
if (!NIL_P(env))
rb_execarg_setenv(execarg_obj, env);
}
rb_io_extract_modeenc(&pmode, 0, opt, &oflags, &fmode, &convconfig);
modestr = rb_io_oflags_modestr(oflags);
port = pipe_open(execarg_obj, modestr, fmode, &convconfig);
if (NIL_P(port)) {
/* child */
if (rb_block_given_p()) {
rb_yield(Qnil);
rb_io_flush(rb_stdout);
rb_io_flush(rb_stderr);
_exit(0);
}
return Qnil;
}
RBASIC(port)->klass = klass;
if (rb_block_given_p()) {
return rb_ensure(rb_yield, port, io_close, port);
}
return port;
}
Opens the file, optionally seeks to the given offset, then
returns length bytes (defaulting to the rest of the file).
read ensures the file is closed before returning.
If the last argument is a hash, it specifies option for internal open(). The key would be the following. open_args: is exclusive to others.
- encoding
-
string or encoding
specifies encoding of the read string.
encodingwill be ignored if length is specified. - mode
-
string
specifies mode argument for open(). It should start with “r” otherwise it will cause an error.
- open_args
-
array of strings
specifies arguments for open() as an array.
Examples:
IO.read("testfile") #=> "This is line one\nThis is line two\nThis is line three\nAnd so on...\n" IO.read("testfile", 20) #=> "This is line one\nThi" IO.read("testfile", 20, 10) #=> "ne one\nThis is line "
static VALUE
rb_io_s_read(int argc, VALUE *argv, VALUE io)
{
VALUE opt, offset;
struct foreach_arg arg;
argc = rb_scan_args(argc, argv, "13:", NULL, NULL, &offset, NULL, &opt);
open_key_args(argc, argv, opt, &arg);
if (NIL_P(arg.io)) return Qnil;
if (!NIL_P(offset)) {
struct seek_arg sarg;
int state = 0;
sarg.io = arg.io;
sarg.offset = offset;
sarg.mode = SEEK_SET;
rb_protect(seek_before_access, (VALUE)&sarg, &state);
if (state) {
rb_io_close(arg.io);
rb_jump_tag(state);
}
if (arg.argc == 2) arg.argc = 1;
}
return rb_ensure(io_s_read, (VALUE)&arg, rb_io_close, arg.io);
}
Reads the entire file specified by name as individual lines, and returns those lines in an array. Lines are separated by sep.
a = IO.readlines("testfile") a[0] #=> "This is line one\n"
If the last argument is a hash, it's the keyword argument to open. See
IO.read for detail.
static VALUE
rb_io_s_readlines(int argc, VALUE *argv, VALUE io)
{
VALUE opt;
struct foreach_arg arg;
argc = rb_scan_args(argc, argv, "13:", NULL, NULL, NULL, NULL, &opt);
open_key_args(argc, argv, opt, &arg);
if (NIL_P(arg.io)) return Qnil;
return rb_ensure(io_s_readlines, (VALUE)&arg, rb_io_close, arg.io);
}
Calls select(2) system call. It monitors given arrays of IO
objects, waits one or more of IO objects ready for reading,
are ready for writing, and have pending exceptions respectably, and returns
an array that contains arrays of those IO objects.
It will return nil if optional timeout value is given
and no IO object is ready in timeout seconds.
Parameters¶ ↑
- read_array
-
an array of
IOobjects that wait until ready for read - write_array
-
an array of
IOobjects that wait until ready for write - error_array
-
an array of
IOobjects that wait for exceptions - timeout
-
a numeric value in second
Example¶ ↑
rp, wp = IO.pipe mesg = "ping " 100.times { rs, ws, = IO.select([rp], [wp]) if r = rs[0] ret = r.read(5) print ret case ret when /ping/ mesg = "pong\n" when /pong/ mesg = "ping " end end if w = ws[0] w.write(mesg) end }
produces:
ping pong ping pong ping pong (snipped) ping
static VALUE
rb_f_select(int argc, VALUE *argv, VALUE obj)
{
VALUE timeout;
struct select_args args;
struct timeval timerec;
int i;
rb_scan_args(argc, argv, "13", &args.read, &args.write, &args.except, &timeout);
if (NIL_P(timeout)) {
args.timeout = 0;
}
else {
timerec = rb_time_interval(timeout);
args.timeout = &timerec;
}
for (i = 0; i < numberof(args.fdsets); ++i)
rb_fd_init(&args.fdsets[i]);
return rb_ensure(select_call, (VALUE)&args, select_end, (VALUE)&args);
}
Opens the given path, returning the underlying file descriptor as a
Fixnum.
IO.sysopen("testfile") #=> 3
static VALUE
rb_io_s_sysopen(int argc, VALUE *argv)
{
VALUE fname, vmode, vperm;
VALUE intmode;
int oflags, fd;
mode_t perm;
rb_scan_args(argc, argv, "12", &fname, &vmode, &vperm);
FilePathValue(fname);
if (NIL_P(vmode))
oflags = O_RDONLY;
else if (!NIL_P(intmode = rb_check_to_integer(vmode, "to_int")))
oflags = NUM2INT(intmode);
else {
SafeStringValue(vmode);
oflags = rb_io_modestr_oflags(StringValueCStr(vmode));
}
if (NIL_P(vperm)) perm = 0666;
else perm = NUM2MODET(vperm);
RB_GC_GUARD(fname) = rb_str_new4(fname);
fd = rb_sysopen(fname, oflags, perm);
return INT2NUM(fd);
}
Try to convert obj into an IO, using #to_io method. Returns converted IO or nil if obj cannot be converted for any reason.
IO.try_convert(STDOUT) #=> STDOUT IO.try_convert("STDOUT") #=> nil require 'zlib' f = open("/tmp/zz.gz") #=> #<File:/tmp/zz.gz> z = Zlib::GzipReader.open(f) #=> #<Zlib::GzipReader:0x81d8744> IO.try_convert(z) #=> #<File:/tmp/zz.gz>
static VALUE
rb_io_s_try_convert(VALUE dummy, VALUE io)
{
return rb_io_check_io(io);
}
Opens the file, optionally seeks to the given offset, writes
string, then returns the length written. write
ensures the file is closed before returning. If offset is not
given, the file is truncated. Otherwise, it is not truncated.
If the last argument is a hash, it specifies option for internal open(). The key would be the following. open_args: is exclusive to others.
encoding: string or encoding
specifies encoding of the read string. encoding will be ignored
if length is specified.
mode: string
specifies mode argument for open(). it should start with "w" or "a" or "r+"
otherwise it would cause error.
perm: fixnum
specifies perm argument for open().
open_args: array
specifies arguments for open() as an array.
IO.write("testfile", "0123456789", 20) # => 10
# File could contain: "This is line one\nThi0123456789two\nThis is line three\nAnd so on...\n"
IO.write("testfile", "0123456789") #=> 10
# File would now read: "0123456789"
static VALUE
rb_io_s_write(int argc, VALUE *argv, VALUE io)
{
return io_s_write(argc, argv, 0);
}
Public Instance Methods
String Output—Writes obj to ios. obj will be
converted to a string using to_s.
$stdout << "Hello " << "world!\n"
produces:
Hello world!
VALUE
rb_io_addstr(VALUE io, VALUE str)
{
rb_io_write(io, str);
return io;
}
Announce an intention to access data from the current file in a specific pattern. On platforms that do not support the <em>posix_fadvise(2)</em> system call, this method is a no-op.
advice is one of the following symbols:
* :normal - No advice to give; the default assumption for an open file. * :sequential - The data will be accessed sequentially: with lower offsets read before higher ones. * :random - The data will be accessed in random order. * :willneed - The data will be accessed in the near future. * :dontneed - The data will not be accessed in the near future. * :noreuse - The data will only be accessed once.
The semantics of a piece of advice are platform-dependent. See man 2 posix_fadvise for details.
"data" means the region of the current file that begins at _offset_ and extends for _len_ bytes. If _len_ is 0, the region ends at the last byte of the file. By default, both _offset_ and _len_ are 0, meaning that the advice applies to the entire file. If an error occurs, one of the following exceptions will be raised: * <code>IOError</code> - The <code>IO</code> stream is closed. * <code>Errno::EBADF</code> - The file descriptor of the current file is invalid. * <code>Errno::EINVAL</code> - An invalid value for _advice_ was given. * <code>Errno::ESPIPE</code> - The file descriptor of the current * file refers to a FIFO or pipe. (Linux raises <code>Errno::EINVAL</code> * in this case). * <code>TypeError</code> - Either _advice_ was not a Symbol, or one of the other arguments was not an <code>Integer</code>. * <code>RangeError</code> - One of the arguments given was too big/small.
- This list is not exhaustive; other Errno
-
exceptions are also possible.
static VALUE
rb_io_advise(int argc, VALUE *argv, VALUE io)
{
VALUE advice, offset, len;
off_t off, l;
rb_io_t *fptr;
rb_scan_args(argc, argv, "12", &advice, &offset, &len);
advice_arg_check(advice);
io = GetWriteIO(io);
GetOpenFile(io, fptr);
off = NIL_P(offset) ? 0 : NUM2OFFT(offset);
l = NIL_P(len) ? 0 : NUM2OFFT(len);
#ifdef HAVE_POSIX_FADVISE
return do_io_advise(fptr, advice, off, l);
#else
((void)off, (void)l); /* Ignore all hint */
return Qnil;
#endif
}
Sets auto-close flag.
f = open("/dev/null") IO.for_fd(f.fileno) # ... f.gets # may cause IOError f = open("/dev/null") IO.for_fd(f.fileno).autoclose = true # ... f.gets # won't cause IOError
static VALUE
rb_io_set_autoclose(VALUE io, VALUE autoclose)
{
rb_io_t *fptr;
rb_secure(4);
GetOpenFile(io, fptr);
if (!RTEST(autoclose))
fptr->mode |= FMODE_PREP;
else
fptr->mode &= ~FMODE_PREP;
return io;
}
Returns true if the underlying file descriptor of ios
will be closed automatically at its finalization, otherwise
false.
static VALUE
rb_io_autoclose_p(VALUE io)
{
rb_io_t *fptr = RFILE(io)->fptr;
rb_secure(4);
rb_io_check_closed(fptr);
return (fptr->mode & FMODE_PREP) ? Qfalse : Qtrue;
}
Puts ios into binary mode. Once a stream is in binary mode, it cannot be reset to nonbinary mode.
-
newline conversion disabled
-
encoding conversion disabled
-
content is treated as ASCII-8BIT
static VALUE
rb_io_binmode_m(VALUE io)
{
VALUE write_io;
rb_io_ascii8bit_binmode(io);
write_io = GetWriteIO(io);
if (write_io != io)
rb_io_ascii8bit_binmode(write_io);
return io;
}
Returns true if ios is binmode.
static VALUE
rb_io_binmode_p(VALUE io)
{
rb_io_t *fptr;
GetOpenFile(io, fptr);
return fptr->mode & FMODE_BINMODE ? Qtrue : Qfalse;
}
This is a deprecated alias for each_byte.
static VALUE
rb_io_bytes(VALUE io)
{
rb_warn("IO#bytes is deprecated; use #each_byte instead");
if (!rb_block_given_p())
return rb_enumeratorize(io, ID2SYM(rb_intern("each_byte")), 0, 0);
return rb_io_each_byte(io);
}
This is a deprecated alias for each_char.
static VALUE
rb_io_chars(VALUE io)
{
rb_warn("IO#chars is deprecated; use #each_char instead");
if (!rb_block_given_p())
return rb_enumeratorize(io, ID2SYM(rb_intern("each_char")), 0, 0);
return rb_io_each_char(io);
}
Closes ios and flushes any pending writes to the operating system.
The stream is unavailable for any further data operations; an
IOError is raised if such an attempt is made. I/O streams are
automatically closed when they are claimed by the garbage collector.
If ios is opened by IO.popen, close sets
$?.
static VALUE
rb_io_close_m(VALUE io)
{
if (rb_safe_level() >= 4 && !OBJ_UNTRUSTED(io)) {
rb_raise(rb_eSecurityError, "Insecure: can't close");
}
rb_io_check_closed(RFILE(io)->fptr);
rb_io_close(io);
return Qnil;
}
Sets a close-on-exec flag.
f = open("/dev/null") f.close_on_exec = true system("cat", "/proc/self/fd/#{f.fileno}") # cat: /proc/self/fd/3: No such file or directory f.closed? #=> false
Ruby sets close-on-exec flags of all file descriptors by default since Ruby 2.0.0. So you don't need to set by yourself. Also, unsetting a close-on-exec flag can cause file descriptor leak if another thread use fork() and exec() (via system() method for example). If you really needs file descriptor inheritance to child process, use spawn()'s argument such as fd=>fd.
static VALUE
rb_io_set_close_on_exec(VALUE io, VALUE arg)
{
int flag = RTEST(arg) ? FD_CLOEXEC : 0;
rb_io_t *fptr;
VALUE write_io;
int fd, ret;
write_io = GetWriteIO(io);
if (io != write_io) {
GetOpenFile(write_io, fptr);
if (fptr && 0 <= (fd = fptr->fd)) {
if ((ret = fcntl(fptr->fd, F_GETFD)) == -1) rb_sys_fail_path(fptr->pathv);
if ((ret & FD_CLOEXEC) != flag) {
ret = (ret & ~FD_CLOEXEC) | flag;
ret = fcntl(fd, F_SETFD, ret);
if (ret == -1) rb_sys_fail_path(fptr->pathv);
}
}
}
GetOpenFile(io, fptr);
if (fptr && 0 <= (fd = fptr->fd)) {
if ((ret = fcntl(fd, F_GETFD)) == -1) rb_sys_fail_path(fptr->pathv);
if ((ret & FD_CLOEXEC) != flag) {
ret = (ret & ~FD_CLOEXEC) | flag;
ret = fcntl(fd, F_SETFD, ret);
if (ret == -1) rb_sys_fail_path(fptr->pathv);
}
}
return Qnil;
}
Returns true if ios will be closed on exec.
f = open("/dev/null") f.close_on_exec? #=> false f.close_on_exec = true f.close_on_exec? #=> true f.close_on_exec = false f.close_on_exec? #=> false
static VALUE
rb_io_close_on_exec_p(VALUE io)
{
rb_io_t *fptr;
VALUE write_io;
int fd, ret;
write_io = GetWriteIO(io);
if (io != write_io) {
GetOpenFile(write_io, fptr);
if (fptr && 0 <= (fd = fptr->fd)) {
if ((ret = fcntl(fd, F_GETFD)) == -1) rb_sys_fail_path(fptr->pathv);
if (!(ret & FD_CLOEXEC)) return Qfalse;
}
}
GetOpenFile(io, fptr);
if (fptr && 0 <= (fd = fptr->fd)) {
if ((ret = fcntl(fd, F_GETFD)) == -1) rb_sys_fail_path(fptr->pathv);
if (!(ret & FD_CLOEXEC)) return Qfalse;
}
return Qtrue;
}
Closes the read end of a duplex I/O stream (i.e., one that contains both a
read and a write stream, such as a pipe). Will raise an
IOError if the stream is not duplexed.
f = IO.popen("/bin/sh","r+") f.close_read f.readlines
produces:
prog.rb:3:in `readlines': not opened for reading (IOError) from prog.rb:3
static VALUE
rb_io_close_read(VALUE io)
{
rb_io_t *fptr;
VALUE write_io;
if (rb_safe_level() >= 4 && !OBJ_UNTRUSTED(io)) {
rb_raise(rb_eSecurityError, "Insecure: can't close");
}
GetOpenFile(io, fptr);
if (is_socket(fptr->fd, fptr->pathv)) {
#ifndef SHUT_RD
# define SHUT_RD 0
#endif
if (shutdown(fptr->fd, SHUT_RD) < 0)
rb_sys_fail_path(fptr->pathv);
fptr->mode &= ~FMODE_READABLE;
if (!(fptr->mode & FMODE_WRITABLE))
return rb_io_close(io);
return Qnil;
}
write_io = GetWriteIO(io);
if (io != write_io) {
rb_io_t *wfptr;
GetOpenFile(write_io, wfptr);
wfptr->pid = fptr->pid;
fptr->pid = 0;
RFILE(io)->fptr = wfptr;
/* bind to write_io temporarily to get rid of memory/fd leak */
fptr->tied_io_for_writing = 0;
fptr->mode &= ~FMODE_DUPLEX;
RFILE(write_io)->fptr = fptr;
rb_io_fptr_cleanup(fptr, FALSE);
/* should not finalize fptr because another thread may be reading it */
return Qnil;
}
if (fptr->mode & FMODE_WRITABLE) {
rb_raise(rb_eIOError, "closing non-duplex IO for reading");
}
return rb_io_close(io);
}
Closes the write end of a duplex I/O stream (i.e., one that contains both a
read and a write stream, such as a pipe). Will raise an
IOError if the stream is not duplexed.
f = IO.popen("/bin/sh","r+") f.close_write f.print "nowhere"
produces:
prog.rb:3:in `write': not opened for writing (IOError) from prog.rb:3:in `print' from prog.rb:3
static VALUE
rb_io_close_write(VALUE io)
{
rb_io_t *fptr;
VALUE write_io;
if (rb_safe_level() >= 4 && !OBJ_UNTRUSTED(io)) {
rb_raise(rb_eSecurityError, "Insecure: can't close");
}
write_io = GetWriteIO(io);
GetOpenFile(write_io, fptr);
if (is_socket(fptr->fd, fptr->pathv)) {
#ifndef SHUT_WR
# define SHUT_WR 1
#endif
if (shutdown(fptr->fd, SHUT_WR) < 0)
rb_sys_fail_path(fptr->pathv);
fptr->mode &= ~FMODE_WRITABLE;
if (!(fptr->mode & FMODE_READABLE))
return rb_io_close(write_io);
return Qnil;
}
if (fptr->mode & FMODE_READABLE) {
rb_raise(rb_eIOError, "closing non-duplex IO for writing");
}
if (io != write_io) {
GetOpenFile(io, fptr);
fptr->tied_io_for_writing = 0;
fptr->mode &= ~FMODE_DUPLEX;
}
rb_io_close(write_io);
return Qnil;
}
Returns true if ios is completely closed (for duplex
streams, both reader and writer), false otherwise.
f = File.new("testfile") f.close #=> nil f.closed? #=> true f = IO.popen("/bin/sh","r+") f.close_write #=> nil f.closed? #=> false f.close_read #=> nil f.closed? #=> true
static VALUE
rb_io_closed(VALUE io)
{
rb_io_t *fptr;
VALUE write_io;
rb_io_t *write_fptr;
write_io = GetWriteIO(io);
if (io != write_io) {
write_fptr = RFILE(write_io)->fptr;
if (write_fptr && 0 <= write_fptr->fd) {
return Qfalse;
}
}
fptr = RFILE(io)->fptr;
rb_io_check_initialized(fptr);
return 0 <= fptr->fd ? Qfalse : Qtrue;
}
This is a deprecated alias for each_codepoint.
static VALUE
rb_io_codepoints(VALUE io)
{
rb_warn("IO#codepoints is deprecated; use #each_codepoint instead");
if (!rb_block_given_p())
return rb_enumeratorize(io, ID2SYM(rb_intern("each_codepoint")), 0, 0);
return rb_io_each_codepoint(io);
}
Yields self within cooked mode.
STDIN.cooked(&:gets)
will read and return a line with echo back and line editing.
You must require 'io/console' to use this method.
static VALUE
console_cooked(VALUE io)
{
return ttymode(io, rb_yield, set_cookedmode, NULL);
}
Enables cooked mode.
If the terminal mode needs to be back, use io.cooked { … }.
You must require 'io/console' to use this method.
static VALUE
console_set_cooked(VALUE io)
{
conmode t;
rb_io_t *fptr;
int fd;
GetOpenFile(io, fptr);
fd = GetReadFD(fptr);
if (!getattr(fd, &t)) rb_sys_fail(0);
set_cookedmode(&t, NULL);
if (!setattr(fd, &t)) rb_sys_fail(0);
return io;
}
Executes the block for every line in ios, where lines are
separated by sep. ios must be opened for reading or an
IOError will be raised.
If no block is given, an enumerator is returned instead.
f = File.new("testfile") f.each {|line| puts "#{f.lineno}: #{line}" }
produces:
1: This is line one 2: This is line two 3: This is line three 4: And so on...
static VALUE
rb_io_each_line(int argc, VALUE *argv, VALUE io)
{
VALUE str, rs;
long limit;
RETURN_ENUMERATOR(io, argc, argv);
prepare_getline_args(argc, argv, &rs, &limit, io);
if (limit == 0)
rb_raise(rb_eArgError, "invalid limit: 0 for each_line");
while (!NIL_P(str = rb_io_getline_1(rs, limit, io))) {
rb_yield(str);
}
return io;
}
Calls the given block once for each byte (0..255) in ios, passing
the byte as an argument. The stream must be opened for reading or an
IOError will be raised.
If no block is given, an enumerator is returned instead.
f = File.new("testfile") checksum = 0 f.each_byte {|x| checksum ^= x } #=> #<File:testfile> checksum #=> 12
static VALUE
rb_io_each_byte(VALUE io)
{
rb_io_t *fptr;
RETURN_ENUMERATOR(io, 0, 0);
GetOpenFile(io, fptr);
for (;;) {
while (fptr->rbuf.len > 0) {
char *p = fptr->rbuf.ptr + fptr->rbuf.off++;
fptr->rbuf.len--;
rb_yield(INT2FIX(*p & 0xff));
errno = 0;
}
rb_io_check_byte_readable(fptr);
READ_CHECK(fptr);
if (io_fillbuf(fptr) < 0) {
break;
}
}
return io;
}
Calls the given block once for each character in ios, passing the
character as an argument. The stream must be opened for reading or an
IOError will be raised.
If no block is given, an enumerator is returned instead.
f = File.new("testfile") f.each_char {|c| print c, ' ' } #=> #<File:testfile>
static VALUE
rb_io_each_char(VALUE io)
{
rb_io_t *fptr;
rb_encoding *enc;
VALUE c;
RETURN_ENUMERATOR(io, 0, 0);
GetOpenFile(io, fptr);
rb_io_check_char_readable(fptr);
enc = io_input_encoding(fptr);
READ_CHECK(fptr);
while (!NIL_P(c = io_getc(fptr, enc))) {
rb_yield(c);
}
return io;
}
Passes the Integer ordinal of each character in ios,
passing the codepoint as an argument. The stream must be opened for reading
or an IOError will be raised.
If no block is given, an enumerator is returned instead.
static VALUE
rb_io_each_codepoint(VALUE io)
{
rb_io_t *fptr;
rb_encoding *enc;
unsigned int c;
int r, n;
RETURN_ENUMERATOR(io, 0, 0);
GetOpenFile(io, fptr);
rb_io_check_char_readable(fptr);
READ_CHECK(fptr);
if (NEED_READCONV(fptr)) {
SET_BINARY_MODE(fptr);
for (;;) {
make_readconv(fptr, 0);
for (;;) {
if (fptr->cbuf.len) {
if (fptr->encs.enc)
r = rb_enc_precise_mbclen(fptr->cbuf.ptr+fptr->cbuf.off,
fptr->cbuf.ptr+fptr->cbuf.off+fptr->cbuf.len,
fptr->encs.enc);
else
r = ONIGENC_CONSTRUCT_MBCLEN_CHARFOUND(1);
if (!MBCLEN_NEEDMORE_P(r))
break;
if (fptr->cbuf.len == fptr->cbuf.capa) {
rb_raise(rb_eIOError, "too long character");
}
}
if (more_char(fptr) == MORE_CHAR_FINISHED) {
clear_readconv(fptr);
/* ignore an incomplete character before EOF */
return io;
}
}
if (MBCLEN_INVALID_P(r)) {
rb_raise(rb_eArgError, "invalid byte sequence in %s",
rb_enc_name(fptr->encs.enc));
}
n = MBCLEN_CHARFOUND_LEN(r);
if (fptr->encs.enc) {
c = rb_enc_codepoint(fptr->cbuf.ptr+fptr->cbuf.off,
fptr->cbuf.ptr+fptr->cbuf.off+fptr->cbuf.len,
fptr->encs.enc);
}
else {
c = (unsigned char)fptr->cbuf.ptr[fptr->cbuf.off];
}
fptr->cbuf.off += n;
fptr->cbuf.len -= n;
rb_yield(UINT2NUM(c));
}
}
NEED_NEWLINE_DECORATOR_ON_READ_CHECK(fptr);
enc = io_input_encoding(fptr);
for (;;) {
if (io_fillbuf(fptr) < 0) {
return io;
}
r = rb_enc_precise_mbclen(fptr->rbuf.ptr+fptr->rbuf.off,
fptr->rbuf.ptr+fptr->rbuf.off+fptr->rbuf.len, enc);
if (MBCLEN_CHARFOUND_P(r) &&
(n = MBCLEN_CHARFOUND_LEN(r)) <= fptr->rbuf.len) {
c = rb_enc_codepoint(fptr->rbuf.ptr+fptr->rbuf.off,
fptr->rbuf.ptr+fptr->rbuf.off+fptr->rbuf.len, enc);
fptr->rbuf.off += n;
fptr->rbuf.len -= n;
rb_yield(UINT2NUM(c));
}
else if (MBCLEN_INVALID_P(r)) {
rb_raise(rb_eArgError, "invalid byte sequence in %s", rb_enc_name(enc));
}
else {
continue;
}
}
return io;
}
Executes the block for every line in ios, where lines are
separated by sep. ios must be opened for reading or an
IOError will be raised.
If no block is given, an enumerator is returned instead.
f = File.new("testfile") f.each {|line| puts "#{f.lineno}: #{line}" }
produces:
1: This is line one 2: This is line two 3: This is line three 4: And so on...
static VALUE
rb_io_each_line(int argc, VALUE *argv, VALUE io)
{
VALUE str, rs;
long limit;
RETURN_ENUMERATOR(io, argc, argv);
prepare_getline_args(argc, argv, &rs, &limit, io);
if (limit == 0)
rb_raise(rb_eArgError, "invalid limit: 0 for each_line");
while (!NIL_P(str = rb_io_getline_1(rs, limit, io))) {
rb_yield(str);
}
return io;
}
Enables/disables echo back. On some platforms, all combinations of this flags and raw/cooked mode may not be valid.
You must require 'io/console' to use this method.
static VALUE
console_set_echo(VALUE io, VALUE f)
{
conmode t;
rb_io_t *fptr;
int fd;
GetOpenFile(io, fptr);
fd = GetReadFD(fptr);
if (!getattr(fd, &t)) rb_sys_fail(0);
if (RTEST(f))
set_echo(&t, NULL);
else
set_noecho(&t, NULL);
if (!setattr(fd, &t)) rb_sys_fail(0);
return io;
}
Returns true if echo back is enabled.
You must require 'io/console' to use this method.
static VALUE
console_echo_p(VALUE io)
{
conmode t;
rb_io_t *fptr;
int fd;
GetOpenFile(io, fptr);
fd = GetReadFD(fptr);
if (!getattr(fd, &t)) rb_sys_fail(0);
return echo_p(&t) ? Qtrue : Qfalse;
}
Returns true if ios is at end of file that means there are no more
data to read. The stream must be opened for reading or an
IOError will be raised.
f = File.new("testfile") dummy = f.readlines f.eof #=> true
If ios is a stream such as pipe or socket, IO#eof?
blocks until the other end sends some data or closes it.
r, w = IO.pipe Thread.new { sleep 1; w.close } r.eof? #=> true after 1 second blocking r, w = IO.pipe Thread.new { sleep 1; w.puts "a" } r.eof? #=> false after 1 second blocking r, w = IO.pipe r.eof? # blocks forever
Note that IO#eof? reads data to the input byte buffer. So
IO#sysread may not behave as you intend with
IO#eof?, unless you call IO#rewind first (which
is not available for some streams).
VALUE
rb_io_eof(VALUE io)
{
rb_io_t *fptr;
GetOpenFile(io, fptr);
rb_io_check_char_readable(fptr);
if (READ_CHAR_PENDING(fptr)) return Qfalse;
if (READ_DATA_PENDING(fptr)) return Qfalse;
READ_CHECK(fptr);
#if defined(RUBY_TEST_CRLF_ENVIRONMENT) || defined(_WIN32)
if (!NEED_READCONV(fptr) && NEED_NEWLINE_DECORATOR_ON_READ(fptr)) {
return eof(fptr->fd) ? Qtrue : Qfalse;
}
#endif
if (io_fillbuf(fptr) < 0) {
return Qtrue;
}
return Qfalse;
}
Returns true if ios is at end of file that means there are no more
data to read. The stream must be opened for reading or an
IOError will be raised.
f = File.new("testfile") dummy = f.readlines f.eof #=> true
If ios is a stream such as pipe or socket, IO#eof?
blocks until the other end sends some data or closes it.
r, w = IO.pipe Thread.new { sleep 1; w.close } r.eof? #=> true after 1 second blocking r, w = IO.pipe Thread.new { sleep 1; w.puts "a" } r.eof? #=> false after 1 second blocking r, w = IO.pipe r.eof? # blocks forever
Note that IO#eof? reads data to the input byte buffer. So
IO#sysread may not behave as you intend with
IO#eof?, unless you call IO#rewind first (which
is not available for some streams).
VALUE
rb_io_eof(VALUE io)
{
rb_io_t *fptr;
GetOpenFile(io, fptr);
rb_io_check_char_readable(fptr);
if (READ_CHAR_PENDING(fptr)) return Qfalse;
if (READ_DATA_PENDING(fptr)) return Qfalse;
READ_CHECK(fptr);
#if defined(RUBY_TEST_CRLF_ENVIRONMENT) || defined(_WIN32)
if (!NEED_READCONV(fptr) && NEED_NEWLINE_DECORATOR_ON_READ(fptr)) {
return eof(fptr->fd) ? Qtrue : Qfalse;
}
#endif
if (io_fillbuf(fptr) < 0) {
return Qtrue;
}
return Qfalse;
}
Reads from the IO until the given
pattern matches or the timeout is over.
It returns an array with the read buffer, followed by the matches. If a block is given, the result is yielded to the block and returns nil.
When called without a block, it waits until the input that matches the
given pattern is obtained from the IO or
the time specified as the timeout passes. An array is returned when the
pattern is obtained from the IO. The first element of
the array is the entire string obtained from the IO
until the pattern matches, followed by elements indicating which the
pattern which matched to the anchor in the regular expression.
The optional timeout parameter defines, in seconds, the total time to wait for the pattern. If the timeout expires or eof is found, nil is returned or yielded. However, the buffer in a timeout session is kept for the next expect call. The default timeout is 9999999 seconds.
# File ext/pty/lib/expect.rb, line 32 def expect(pat,timeout=9999999) buf = '' case pat when String e_pat = Regexp.new(Regexp.quote(pat)) when Regexp e_pat = pat else raise TypeError, "unsupported pattern class: #{pat.class}" end @unusedBuf ||= '' while true if not @unusedBuf.empty? c = @unusedBuf.slice!(0).chr elsif !IO.select([self],nil,nil,timeout) or eof? then result = nil @unusedBuf = buf break else c = getc.chr end buf << c if $expect_verbose STDOUT.print c STDOUT.flush end if mat=e_pat.match(buf) then result = [buf,*mat.to_a[1..-1]] break end end if block_given? then yield result else return result end nil end
Returns the Encoding object that represents the
encoding of the file. If io is write mode and no encoding is specified,
returns nil.
static VALUE
rb_io_external_encoding(VALUE io)
{
rb_io_t *fptr;
GetOpenFile(io, fptr);
if (fptr->encs.enc2) {
return rb_enc_from_encoding(fptr->encs.enc2);
}
if (fptr->mode & FMODE_WRITABLE) {
if (fptr->encs.enc)
return rb_enc_from_encoding(fptr->encs.enc);
return Qnil;
}
return rb_enc_from_encoding(io_read_encoding(fptr));
}
Provides a mechanism for issuing low-level commands to control or query
file-oriented I/O streams. Arguments and results are platform dependent. If
arg is a number, its value is passed directly. If it is a string,
it is interpreted as a binary sequence of bytes (Array#pack
might be a useful way to build this string). On Unix platforms, see
fcntl(2) for details. Not implemented on all platforms.
static VALUE
rb_io_fcntl(int argc, VALUE *argv, VALUE io)
{
VALUE req, arg;
rb_scan_args(argc, argv, "11", &req, &arg);
return rb_fcntl(io, req, arg);
}
Immediately writes all buffered data in ios to disk.
If the underlying operating system does not support fdatasync(2),
IO#fsync is called instead (which might raise a
NotImplementedError).
static VALUE
rb_io_fdatasync(VALUE io)
{
rb_io_t *fptr;
io = GetWriteIO(io);
GetOpenFile(io, fptr);
if (io_fflush(fptr) < 0)
rb_sys_fail(0);
if ((int)rb_thread_io_blocking_region(nogvl_fdatasync, fptr, fptr->fd) == 0)
return INT2FIX(0);
/* fall back */
return rb_io_fsync(io);
}
Returns an integer representing the numeric file descriptor for ios.
$stdin.fileno #=> 0 $stdout.fileno #=> 1
static VALUE
rb_io_fileno(VALUE io)
{
rb_io_t *fptr = RFILE(io)->fptr;
int fd;
rb_io_check_closed(fptr);
fd = fptr->fd;
return INT2FIX(fd);
}
Flushes any buffered data within ios to the underlying operating system (note that this is Ruby internal buffering only; the OS may buffer the data as well).
$stdout.print "no newline" $stdout.flush
produces:
no newline
VALUE
rb_io_flush(VALUE io)
{
rb_io_t *fptr;
if (!RB_TYPE_P(io, T_FILE)) {
return rb_funcall(io, id_flush, 0);
}
io = GetWriteIO(io);
GetOpenFile(io, fptr);
if (fptr->mode & FMODE_WRITABLE) {
if (io_fflush(fptr) < 0)
rb_sys_fail(0);
#ifdef _WIN32
if (GetFileType((HANDLE)rb_w32_get_osfhandle(fptr->fd)) == FILE_TYPE_DISK) {
rb_thread_io_blocking_region(nogvl_fsync, fptr, fptr->fd);
}
#endif
}
if (fptr->mode & FMODE_READABLE) {
io_unread(fptr);
}
return io;
}
Immediately writes all buffered data in ios to disk. Note that
fsync differs from using IO#sync=. The latter
ensures that data is flushed from Ruby's buffers, but does not
guarantee that the underlying operating system actually writes it to disk.
NotImplementedError is raised if the underlying operating
system does not support fsync(2).
static VALUE
rb_io_fsync(VALUE io)
{
rb_io_t *fptr;
io = GetWriteIO(io);
GetOpenFile(io, fptr);
if (io_fflush(fptr) < 0)
rb_sys_fail(0);
# ifndef _WIN32 /* already called in io_fflush() */
if ((int)rb_thread_io_blocking_region(nogvl_fsync, fptr, fptr->fd) < 0)
rb_sys_fail_path(fptr->pathv);
# endif
return INT2FIX(0);
}
Gets the next 8-bit byte (0..255) from ios. Returns
nil if called at end of file.
f = File.new("testfile") f.getbyte #=> 84 f.getbyte #=> 104
VALUE
rb_io_getbyte(VALUE io)
{
rb_io_t *fptr;
int c;
GetOpenFile(io, fptr);
rb_io_check_byte_readable(fptr);
READ_CHECK(fptr);
if (fptr->fd == 0 && (fptr->mode & FMODE_TTY) && RB_TYPE_P(rb_stdout, T_FILE)) {
rb_io_t *ofp;
GetOpenFile(rb_stdout, ofp);
if (ofp->mode & FMODE_TTY) {
rb_io_flush(rb_stdout);
}
}
if (io_fillbuf(fptr) < 0) {
return Qnil;
}
fptr->rbuf.off++;
fptr->rbuf.len--;
c = (unsigned char)fptr->rbuf.ptr[fptr->rbuf.off-1];
return INT2FIX(c & 0xff);
}
Reads a one-character string from ios. Returns nil if
called at end of file.
f = File.new("testfile") f.getc #=> "h" f.getc #=> "e"
static VALUE
rb_io_getc(VALUE io)
{
rb_io_t *fptr;
rb_encoding *enc;
GetOpenFile(io, fptr);
rb_io_check_char_readable(fptr);
enc = io_input_encoding(fptr);
READ_CHECK(fptr);
return io_getc(fptr, enc);
}
Reads and returns a character in raw mode.
You must require 'io/console' to use this method.
static VALUE
console_getch(int argc, VALUE *argv, VALUE io)
{
rawmode_arg_t opts, *optp = rawmode_opt(argc, argv, &opts);
return ttymode(io, getc_call, set_rawmode, optp);
}
Reads the next “line'' from the I/O stream; lines are separated by
sep. A separator of nil reads the entire contents,
and a zero-length separator reads the input a paragraph at a time (two
successive newlines in the input separate paragraphs). The stream must be
opened for reading or an IOError will be raised. The line read
in will be returned and also assigned to $_. Returns
nil if called at end of file. If the first argument is an
integer, or optional second argument is given, the returning string would
not be longer than the given value in bytes.
File.new("testfile").gets #=> "This is line one\n" $_ #=> "This is line one\n"
static VALUE
rb_io_gets_m(int argc, VALUE *argv, VALUE io)
{
VALUE str;
str = rb_io_getline(argc, argv, io);
rb_lastline_set(str);
return str;
}
Flushes input buffer in kernel.
You must require 'io/console' to use this method.
static VALUE
console_iflush(VALUE io)
{
rb_io_t *fptr;
int fd;
GetOpenFile(io, fptr);
fd = GetReadFD(fptr);
#if defined HAVE_TERMIOS_H || defined HAVE_TERMIO_H
if (tcflush(fd, TCIFLUSH)) rb_sys_fail(0);
#endif
return io;
}
Return a string describing this IO object.
static VALUE
rb_io_inspect(VALUE obj)
{
rb_io_t *fptr;
VALUE result;
static const char closed[] = " (closed)";
fptr = RFILE(taint_check(obj))->fptr;
if (!fptr) return rb_any_to_s(obj);
result = rb_str_new_cstr("#<");
rb_str_append(result, rb_class_name(CLASS_OF(obj)));
rb_str_cat2(result, ":");
if (NIL_P(fptr->pathv)) {
if (fptr->fd < 0) {
rb_str_cat(result, closed+1, strlen(closed)-1);
}
else {
rb_str_catf(result, "fd %d", fptr->fd);
}
}
else {
rb_str_append(result, fptr->pathv);
if (fptr->fd < 0) {
rb_str_cat(result, closed, strlen(closed));
}
}
return rb_str_cat2(result, ">");
}
Returns the Encoding of the internal string if conversion is specified. Otherwise returns nil.
static VALUE
rb_io_internal_encoding(VALUE io)
{
rb_io_t *fptr;
GetOpenFile(io, fptr);
if (!fptr->encs.enc2) return Qnil;
return rb_enc_from_encoding(io_read_encoding(fptr));
}
Provides a mechanism for issuing low-level commands to control or query I/O
devices. Arguments and results are platform dependent. If arg is a
number, its value is passed directly. If it is a string, it is interpreted
as a binary sequence of bytes. On Unix platforms, see ioctl(2)
for details. Not implemented on all platforms.
static VALUE
rb_io_ioctl(int argc, VALUE *argv, VALUE io)
{
VALUE req, arg;
rb_scan_args(argc, argv, "11", &req, &arg);
return rb_ioctl(io, req, arg);
}
Flushes input and output buffers in kernel.
You must require 'io/console' to use this method.
static VALUE
console_ioflush(VALUE io)
{
rb_io_t *fptr;
#if defined HAVE_TERMIOS_H || defined HAVE_TERMIO_H
int fd1, fd2;
#endif
GetOpenFile(io, fptr);
#if defined HAVE_TERMIOS_H || defined HAVE_TERMIO_H
fd1 = GetReadFD(fptr);
fd2 = GetWriteFD(fptr);
if (fd2 != -1 && fd1 != fd2) {
if (tcflush(fd1, TCIFLUSH)) rb_sys_fail(0);
if (tcflush(fd2, TCOFLUSH)) rb_sys_fail(0);
}
else {
if (tcflush(fd1, TCIOFLUSH)) rb_sys_fail(0);
}
#endif
return io;
}
Returns true if ios is associated with a terminal
device (tty), false otherwise.
File.new("testfile").isatty #=> false File.new("/dev/tty").isatty #=> true
static VALUE
rb_io_isatty(VALUE io)
{
rb_io_t *fptr;
GetOpenFile(io, fptr);
if (isatty(fptr->fd) == 0)
return Qfalse;
return Qtrue;
}
Returns the current line number in ios. The stream must be opened
for reading. lineno counts the number of times gets is called rather than the number of
newlines encountered. The two values will differ if gets is called with a separator other than
newline.
Methods that use $/ like each, lines and readline will also increment
lineno.
See also the $. variable.
f = File.new("testfile") f.lineno #=> 0 f.gets #=> "This is line one\n" f.lineno #=> 1 f.gets #=> "This is line two\n" f.lineno #=> 2
static VALUE
rb_io_lineno(VALUE io)
{
rb_io_t *fptr;
GetOpenFile(io, fptr);
rb_io_check_char_readable(fptr);
return INT2NUM(fptr->lineno);
}
Manually sets the current line number to the given value. $.
is updated only on the next read.
f = File.new("testfile") f.gets #=> "This is line one\n" $. #=> 1 f.lineno = 1000 f.lineno #=> 1000 $. #=> 1 # lineno of last read f.gets #=> "This is line two\n" $. #=> 1001 # lineno of last read
static VALUE
rb_io_set_lineno(VALUE io, VALUE lineno)
{
rb_io_t *fptr;
GetOpenFile(io, fptr);
rb_io_check_char_readable(fptr);
fptr->lineno = NUM2INT(lineno);
return lineno;
}
This is a deprecated alias for each_line.
static VALUE
rb_io_lines(int argc, VALUE *argv, VALUE io)
{
rb_warn("IO#lines is deprecated; use #each_line instead");
if (!rb_block_given_p())
return rb_enumeratorize(io, ID2SYM(rb_intern("each_line")), argc, argv);
return rb_io_each_line(argc, argv, io);
}
Yields self with disabling echo back.
STDIN.noecho(&:gets)
will read and return a line without echo back.
You must require 'io/console' to use this method.
static VALUE
console_noecho(VALUE io)
{
return ttymode(io, rb_yield, set_noecho, NULL);
}
Returns number of bytes that can be read without blocking. Returns zero if no information available.
static VALUE
io_nread(VALUE io)
{
rb_io_t *fptr;
int len;
ioctl_arg n;
GetOpenFile(io, fptr);
rb_io_check_readable(fptr);
len = rb_io_read_pending(fptr);
if (len > 0) return len;
if (!FIONREAD_POSSIBLE_P(fptr->fd)) return INT2FIX(0);
if (ioctl(fptr->fd, FIONREAD, &n)) return INT2FIX(0);
if (n > 0) return ioctl_arg2num(n);
return INT2FIX(0);
}
Flushes output buffer in kernel.
You must require 'io/console' to use this method.
static VALUE
console_oflush(VALUE io)
{
rb_io_t *fptr;
int fd;
GetOpenFile(io, fptr);
fd = GetWriteFD(fptr);
#if defined HAVE_TERMIOS_H || defined HAVE_TERMIO_H
if (tcflush(fd, TCOFLUSH)) rb_sys_fail(0);
#endif
return io;
}
Returns the process ID of a child process associated with ios.
This will be set by IO.popen.
pipe = IO.popen("-") if pipe $stderr.puts "In parent, child pid is #{pipe.pid}" else $stderr.puts "In child, pid is #{$$}" end
produces:
In child, pid is 26209 In parent, child pid is 26209
static VALUE
rb_io_pid(VALUE io)
{
rb_io_t *fptr;
GetOpenFile(io, fptr);
if (!fptr->pid)
return Qnil;
return PIDT2NUM(fptr->pid);
}
Returns the current offset (in bytes) of ios.
f = File.new("testfile") f.pos #=> 0 f.gets #=> "This is line one\n" f.pos #=> 17
static VALUE
rb_io_tell(VALUE io)
{
rb_io_t *fptr;
off_t pos;
GetOpenFile(io, fptr);
pos = io_tell(fptr);
if (pos < 0 && errno) rb_sys_fail_path(fptr->pathv);
pos -= fptr->rbuf.len;
return OFFT2NUM(pos);
}
Seeks to the given position (in bytes) in ios. It is not guranteed that seeking to the right position when ios is textmode.
f = File.new("testfile") f.pos = 17 f.gets #=> "This is line two\n"
static VALUE
rb_io_set_pos(VALUE io, VALUE offset)
{
rb_io_t *fptr;
off_t pos;
pos = NUM2OFFT(offset);
GetOpenFile(io, fptr);
pos = io_seek(fptr, pos, SEEK_SET);
if (pos < 0 && errno) rb_sys_fail_path(fptr->pathv);
return OFFT2NUM(pos);
}
Writes the given object(s) to ios. The stream must be opened for
writing. If the output field separator ($,) is not
nil, it will be inserted between each object. If the output
record separator ($\) is not nil, it will be
appended to the output. If no arguments are given, prints $_.
Objects that aren't strings will be converted by calling their
to_s method. With no argument, prints the contents of the
variable $_. Returns nil.
$stdout.print("This is ", 100, " percent.\n")
produces:
This is 100 percent.
VALUE
rb_io_print(int argc, VALUE *argv, VALUE out)
{
int i;
VALUE line;
/* if no argument given, print `$_' */
if (argc == 0) {
argc = 1;
line = rb_lastline_get();
argv = &line;
}
for (i=0; i<argc; i++) {
if (!NIL_P(rb_output_fs) && i>0) {
rb_io_write(out, rb_output_fs);
}
rb_io_write(out, argv[i]);
}
if (argc > 0 && !NIL_P(rb_output_rs)) {
rb_io_write(out, rb_output_rs);
}
return Qnil;
}
Formats and writes to ios, converting parameters under control of
the format string. See Kernel#sprintf for details.
VALUE
rb_io_printf(int argc, VALUE *argv, VALUE out)
{
rb_io_write(out, rb_f_sprintf(argc, argv));
return Qnil;
}
If obj is Numeric, write the character whose code is
the least-significant byte of obj, otherwise write the first byte
of the string representation of obj to ios. Note: This
method is not safe for use with multi-byte characters as it will truncate
them.
$stdout.putc "A" $stdout.putc 65
produces:
AA
static VALUE
rb_io_putc(VALUE io, VALUE ch)
{
VALUE str;
if (RB_TYPE_P(ch, T_STRING)) {
str = rb_str_substr(ch, 0, 1);
}
else {
char c = NUM2CHR(ch);
str = rb_str_new(&c, 1);
}
rb_io_write(io, str);
return ch;
}
Writes the given objects to ios as with IO#print.
Writes a record separator (typically a newline) after any that do not
already end with a newline sequence. If called with an array argument,
writes each element on a new line. If called without arguments, outputs a
single record separator.
$stdout.puts("this", "is", "a", "test")
produces:
this is a test
VALUE
rb_io_puts(int argc, VALUE *argv, VALUE out)
{
int i;
VALUE line;
/* if no argument given, print newline. */
if (argc == 0) {
rb_io_write(out, rb_default_rs);
return Qnil;
}
for (i=0; i<argc; i++) {
if (RB_TYPE_P(argv[i], T_STRING)) {
line = argv[i];
goto string;
}
if (rb_exec_recursive(io_puts_ary, argv[i], out)) {
continue;
}
line = rb_obj_as_string(argv[i]);
string:
rb_io_write(out, line);
if (RSTRING_LEN(line) == 0 ||
!str_end_with_asciichar(line, '\n')) {
rb_io_write(out, rb_default_rs);
}
}
return Qnil;
}
Yields self within raw mode.
STDIN.raw(&:gets)
will read and return a line without echo back and line editing.
You must require 'io/console' to use this method.
static VALUE
console_raw(int argc, VALUE *argv, VALUE io)
{
rawmode_arg_t opts, *optp = rawmode_opt(argc, argv, &opts);
return ttymode(io, rb_yield, set_rawmode, optp);
}
Enables raw mode.
If the terminal mode needs to be back, use io.raw { … }.
You must require 'io/console' to use this method.
static VALUE
console_set_raw(int argc, VALUE *argv, VALUE io)
{
conmode t;
rb_io_t *fptr;
int fd;
rawmode_arg_t opts, *optp = rawmode_opt(argc, argv, &opts);
GetOpenFile(io, fptr);
fd = GetReadFD(fptr);
if (!getattr(fd, &t)) rb_sys_fail(0);
set_rawmode(&t, optp);
if (!setattr(fd, &t)) rb_sys_fail(0);
return io;
}
Reads length bytes from the I/O stream.
length must be a non-negative integer or nil.
If length is a positive integer, it try to read length
bytes without any conversion (binary mode). It returns nil or
a string whose length is 1 to length bytes. nil means
it met EOF at beginning. The 1 to length-1 bytes string means it
met EOF after reading the result. The length bytes string means it
doesn't meet EOF. The resulted string is always ASCII-8BIT encoding.
If length is omitted or is nil, it reads until EOF
and the encoding conversion is applied. It returns a string even if EOF is
met at beginning.
If length is zero, it returns "".
If the optional outbuf argument is present, it must reference a String, which will receive the data. The outbuf will contain only the received data after the method call even if it is not empty at the beginning.
At end of file, it returns nil or ""
depend on length. ios.read() and
ios.read(nil) returns "".
ios.read(positive-integer) returns
nil.
f = File.new("testfile")
f.read(16) #=> "This is line one"
# reads whole file
open("file") {|f|
data = f.read # This returns a string even if the file is empty.
...
}
# iterate over fixed length records.
open("fixed-record-file") {|f|
while record = f.read(256)
...
end
}
# iterate over variable length records.
# record is prefixed by 32-bit length.
open("variable-record-file") {|f|
while len = f.read(4)
len = len.unpack("N")[0] # 32-bit length
record = f.read(len) # This returns a string even if len is 0.
end
}
Note that this method behaves like fread() function in C. This means it retry to invoke read(2) system call to read data with the specified length (or until EOF). This behavior is preserved even if ios is non-blocking mode. (This method is non-blocking flag insensitive as other methods.) If you need the behavior like single read(2) system call, consider readpartial, #read_nonblock and sysread.
static VALUE
io_read(int argc, VALUE *argv, VALUE io)
{
rb_io_t *fptr;
long n, len;
VALUE length, str;
#if defined(RUBY_TEST_CRLF_ENVIRONMENT) || defined(_WIN32)
int previous_mode;
#endif
rb_scan_args(argc, argv, "02", &length, &str);
if (NIL_P(length)) {
GetOpenFile(io, fptr);
rb_io_check_char_readable(fptr);
return read_all(fptr, remain_size(fptr), str);
}
len = NUM2LONG(length);
if (len < 0) {
rb_raise(rb_eArgError, "negative length %ld given", len);
}
io_setstrbuf(&str,len);
GetOpenFile(io, fptr);
rb_io_check_byte_readable(fptr);
if (len == 0) {
io_set_read_length(str, 0);
return str;
}
READ_CHECK(fptr);
#if defined(RUBY_TEST_CRLF_ENVIRONMENT) || defined(_WIN32)
previous_mode = set_binary_mode_with_seek_cur(fptr);
#endif
n = io_fread(str, 0, len, fptr);
io_set_read_length(str, n);
#if defined(RUBY_TEST_CRLF_ENVIRONMENT) || defined(_WIN32)
if (previous_mode == O_TEXT) {
setmode(fptr->fd, O_TEXT);
}
#endif
if (n == 0) return Qnil;
OBJ_TAINT(str);
return str;
}
Reads at most maxlen bytes from ios using the read(2) system call after O_NONBLOCK is set for the underlying file descriptor.
If the optional outbuf argument is present, it must reference a String, which will receive the data. The outbuf will contain only the received data after the method call even if it is not empty at the beginning.
#read_nonblock just calls the read(2) system call. It causes all errors the read(2) system call causes: Errno::EWOULDBLOCK, Errno::EINTR, etc. The caller should care such errors.
If the exception is Errno::EWOULDBLOCK or Errno::AGAIN, it is extended by IO::WaitReadable. So IO::WaitReadable can be used to rescue the exceptions for retrying read_nonblock.
#read_nonblock causes EOFError on EOF.
If the read byte buffer is not empty, #read_nonblock reads from the buffer like readpartial. In this case, the read(2) system call is not called.
When #read_nonblock raises an exception kind of IO::WaitReadable, #read_nonblock should not be called until io is readable for avoiding busy loop. This can be done as follows.
# emulates blocking read (readpartial). begin result = io.read_nonblock(maxlen) rescue IO::WaitReadable IO.select([io]) retry end
Although #read_nonblock doesn't raise IO::WaitWritable. OpenSSL::Buffering#read_nonblock can raise IO::WaitWritable. If IO and SSL should be used polymorphically, IO::WaitWritable should be rescued too. See the document of OpenSSL::Buffering#read_nonblock for sample code.
Note that this method is identical to readpartial except the non-blocking flag is set.
static VALUE
io_read_nonblock(int argc, VALUE *argv, VALUE io)
{
VALUE ret;
ret = io_getpartial(argc, argv, io, 1);
if (NIL_P(ret))
rb_eof_error();
return ret;
}
Reads a byte as with IO#getbyte, but raises an
EOFError on end of file.
static VALUE
rb_io_readbyte(VALUE io)
{
VALUE c = rb_io_getbyte(io);
if (NIL_P(c)) {
rb_eof_error();
}
return c;
}
Reads a one-character string from ios. Raises an
EOFError on end of file.
f = File.new("testfile") f.readchar #=> "h" f.readchar #=> "e"
static VALUE
rb_io_readchar(VALUE io)
{
VALUE c = rb_io_getc(io);
if (NIL_P(c)) {
rb_eof_error();
}
return c;
}
Reads a line as with IO#gets, but raises an
EOFError on end of file.
static VALUE
rb_io_readline(int argc, VALUE *argv, VALUE io)
{
VALUE line = rb_io_gets_m(argc, argv, io);
if (NIL_P(line)) {
rb_eof_error();
}
return line;
}
Reads all of the lines in ios, and returns them in
anArray. Lines are separated by the optional sep. If
sep is nil, the rest of the stream is returned as a
single record. If the first argument is an integer, or optional second
argument is given, the returning string would not be longer than the given
value in bytes. The stream must be opened for reading or an
IOError will be raised.
f = File.new("testfile") f.readlines[0] #=> "This is line one\n"
static VALUE
rb_io_readlines(int argc, VALUE *argv, VALUE io)
{
VALUE line, ary, rs;
long limit;
prepare_getline_args(argc, argv, &rs, &limit, io);
if (limit == 0)
rb_raise(rb_eArgError, "invalid limit: 0 for readlines");
ary = rb_ary_new();
while (!NIL_P(line = rb_io_getline_1(rs, limit, io))) {
rb_ary_push(ary, line);
}
return ary;
}
Reads at most maxlen bytes from the I/O stream. It blocks only if
ios has no data immediately available. It doesn't block if
some data available. If the optional outbuf argument is present,
it must reference a String, which will receive the data. The
outbuf will contain only the received data after the method call
even if it is not empty at the beginning. It raises EOFError
on end of file.
readpartial is designed for streams such as pipe, socket, tty, etc. It blocks only when no data immediately available. This means that it blocks only when following all conditions hold.
-
the byte buffer in the IO object is empty.
-
the content of the stream is empty.
-
the stream is not reached to EOF.
When readpartial blocks, it waits data or EOF on the stream. If some data is reached, readpartial returns with the data. If EOF is reached, readpartial raises EOFError.
When readpartial doesn't blocks, it returns or raises immediately. If the byte buffer is not empty, it returns the data in the buffer. Otherwise if the stream has some content, it returns the data in the stream. Otherwise if the stream is reached to EOF, it raises EOFError.
r, w = IO.pipe # buffer pipe content w << "abc" # "" "abc". r.readpartial(4096) #=> "abc" "" "" r.readpartial(4096) # blocks because buffer and pipe is empty. r, w = IO.pipe # buffer pipe content w << "abc" # "" "abc" w.close # "" "abc" EOF r.readpartial(4096) #=> "abc" "" EOF r.readpartial(4096) # raises EOFError r, w = IO.pipe # buffer pipe content w << "abc\ndef\n" # "" "abc\ndef\n" r.gets #=> "abc\n" "def\n" "" w << "ghi\n" # "def\n" "ghi\n" r.readpartial(4096) #=> "def\n" "" "ghi\n" r.readpartial(4096) #=> "ghi\n" "" ""
Note that readpartial behaves similar to sysread. The differences are:
-
If the byte buffer is not empty, read from the byte buffer instead of “sysread for buffered IO (IOError)”.
-
It doesn't cause Errno::EWOULDBLOCK and Errno::EINTR. When readpartial meets EWOULDBLOCK and EINTR by read system call, readpartial retry the system call.
The later means that readpartial is nonblocking-flag insensitive. It blocks on the situation #sysread causes Errno::EWOULDBLOCK as if the fd is blocking mode.
static VALUE
io_readpartial(int argc, VALUE *argv, VALUE io)
{
VALUE ret;
ret = io_getpartial(argc, argv, io, 0);
if (NIL_P(ret))
rb_eof_error();
return ret;
}
Returns true if input available without blocking, or false. Returns nil if no information available.
static VALUE
io_ready_p(VALUE io)
{
rb_io_t *fptr;
ioctl_arg n;
GetOpenFile(io, fptr);
rb_io_check_readable(fptr);
if (rb_io_read_pending(fptr)) return Qtrue;
if (!FIONREAD_POSSIBLE_P(fptr->fd)) return Qnil;
if (ioctl(fptr->fd, FIONREAD, &n)) return Qnil;
if (n > 0) return Qtrue;
return Qfalse;
}
Reassociates ios with the I/O stream given in other_IO or to a new stream opened on path. This may dynamically change the actual class of this stream.
f1 = File.new("testfile") f2 = File.new("testfile") f2.readlines[0] #=> "This is line one\n" f2.reopen(f1) #=> #<File:testfile> f2.readlines[0] #=> "This is line one\n"
static VALUE
rb_io_reopen(int argc, VALUE *argv, VALUE file)
{
VALUE fname, nmode, opt;
int oflags;
rb_io_t *fptr;
rb_secure(4);
if (rb_scan_args(argc, argv, "11:", &fname, &nmode, &opt) == 1) {
VALUE tmp = rb_io_check_io(fname);
if (!NIL_P(tmp)) {
return io_reopen(file, tmp);
}
}
FilePathValue(fname);
rb_io_taint_check(file);
fptr = RFILE(file)->fptr;
if (!fptr) {
fptr = RFILE(file)->fptr = ALLOC(rb_io_t);
MEMZERO(fptr, rb_io_t, 1);
}
if (!NIL_P(nmode) || !NIL_P(opt)) {
int fmode;
convconfig_t convconfig;
rb_io_extract_modeenc(&nmode, 0, opt, &oflags, &fmode, &convconfig);
if (IS_PREP_STDIO(fptr) &&
((fptr->mode & FMODE_READWRITE) & (fmode & FMODE_READWRITE)) !=
(fptr->mode & FMODE_READWRITE)) {
rb_raise(rb_eArgError,
"%s can't change access mode from \"%s\" to \"%s\"",
PREP_STDIO_NAME(fptr), rb_io_fmode_modestr(fptr->mode),
rb_io_fmode_modestr(fmode));
}
fptr->mode = fmode;
fptr->encs = convconfig;
}
else {
oflags = rb_io_fmode_oflags(fptr->mode);
}
fptr->pathv = rb_str_new_frozen(fname);
if (fptr->fd < 0) {
fptr->fd = rb_sysopen(fptr->pathv, oflags, 0666);
fptr->stdio_file = 0;
return file;
}
if (fptr->mode & FMODE_WRITABLE) {
if (io_fflush(fptr) < 0)
rb_sys_fail(0);
}
fptr->rbuf.off = fptr->rbuf.len = 0;
if (fptr->stdio_file) {
if (freopen(RSTRING_PTR(fptr->pathv), rb_io_oflags_modestr(oflags), fptr->stdio_file) == 0) {
rb_sys_fail_path(fptr->pathv);
}
fptr->fd = fileno(fptr->stdio_file);
rb_fd_fix_cloexec(fptr->fd);
#ifdef USE_SETVBUF
if (setvbuf(fptr->stdio_file, NULL, _IOFBF, 0) != 0)
rb_warn("setvbuf() can't be honoured for %s", RSTRING_PTR(fptr->pathv));
#endif
if (fptr->stdio_file == stderr) {
if (setvbuf(fptr->stdio_file, NULL, _IONBF, BUFSIZ) != 0)
rb_warn("setvbuf() can't be honoured for %s", RSTRING_PTR(fptr->pathv));
}
else if (fptr->stdio_file == stdout && isatty(fptr->fd)) {
if (setvbuf(fptr->stdio_file, NULL, _IOLBF, BUFSIZ) != 0)
rb_warn("setvbuf() can't be honoured for %s", RSTRING_PTR(fptr->pathv));
}
}
else {
int tmpfd = rb_sysopen(fptr->pathv, oflags, 0666);
int err = 0;
if (rb_cloexec_dup2(tmpfd, fptr->fd) < 0)
err = errno;
(void)close(tmpfd);
if (err) {
rb_sys_fail_path(fptr->pathv);
}
}
return file;
}
Positions ios to the beginning of input, resetting
lineno to zero.
f = File.new("testfile") f.readline #=> "This is line one\n" f.rewind #=> 0 f.lineno #=> 0 f.readline #=> "This is line one\n"
Note that it cannot be used with streams such as pipes, ttys, and sockets.
static VALUE
rb_io_rewind(VALUE io)
{
rb_io_t *fptr;
GetOpenFile(io, fptr);
if (io_seek(fptr, 0L, 0) < 0 && errno) rb_sys_fail_path(fptr->pathv);
#ifdef _WIN32
if (GetFileType((HANDLE)rb_w32_get_osfhandle(fptr->fd)) == FILE_TYPE_DISK) {
fsync(fptr->fd);
}
#endif
if (io == ARGF.current_file) {
ARGF.lineno -= fptr->lineno;
}
fptr->lineno = 0;
if (fptr->readconv) {
clear_readconv(fptr);
}
return INT2FIX(0);
}
Scans the current string until the match is exhausted, yielding each match as it is encountered in the string. A block is not necessary though, as the results will simply be aggregated into the final array.
"123 456".block_scanf("%d") # => [123, 456]
If a block is given, the value from that is returned from the yield is added to an output array.
"123 456".block_scanf("%d) do |digit,| # the ',' unpacks the Array
digit + 100
end
# => [223, 556]
See Scanf for details on creating a format string.
You will need to require 'scanf' to use use #scanf.
# File lib/scanf.rb, line 614 def scanf(str,&b) #:yield: current_match return block_scanf(str,&b) if b return [] unless str.size > 0 start_position = pos rescue 0 matched_so_far = 0 source_buffer = "" result_buffer = [] final_result = [] fstr = Scanf::FormatString.new(str) loop do if eof || (tty? &&! fstr.match(source_buffer)) final_result.concat(result_buffer) break end source_buffer << gets current_match = fstr.match(source_buffer) spec = fstr.last_spec_tried if spec.matched if spec.mid_match? result_buffer.replace(current_match) next end elsif (fstr.matched_count == fstr.spec_count - 1) if /\A\s*\z/.match(fstr.string_left) break if spec.count_space? result_buffer.replace(current_match) next end end final_result.concat(current_match) matched_so_far += source_buffer.size source_buffer.replace(fstr.string_left) matched_so_far -= source_buffer.size break if fstr.last_spec fstr.prune end seek(start_position + matched_so_far, IO::SEEK_SET) rescue Errno::ESPIPE soak_up_spaces if fstr.last_spec && fstr.space return final_result end
Seeks to a given offset anInteger in the stream according to the value of whence:
IO::SEEK_CUR | Seeks to _amount_ plus current position
--------------+----------------------------------------------------
IO::SEEK_END | Seeks to _amount_ plus end of stream (you probably
| want a negative value for _amount_)
--------------+----------------------------------------------------
IO::SEEK_SET | Seeks to the absolute location given by _amount_
Example:
f = File.new("testfile") f.seek(-13, IO::SEEK_END) #=> 0 f.readline #=> "And so on...\n"
static VALUE
rb_io_seek_m(int argc, VALUE *argv, VALUE io)
{
VALUE offset, ptrname;
int whence = SEEK_SET;
if (rb_scan_args(argc, argv, "11", &offset, &ptrname) == 2) {
whence = NUM2INT(ptrname);
}
return rb_io_seek(io, offset, whence);
}
If single argument is specified, read string from io is tagged with the encoding specified. If encoding is a colon separated two encoding names “A:B”, the read string is converted from encoding A (external encoding) to encoding B (internal encoding), then tagged with B. If two arguments are specified, those must be encoding objects or encoding names, and the first one is the external encoding, and the second one is the internal encoding. If the external encoding and the internal encoding is specified, optional hash argument specify the conversion option.
static VALUE
rb_io_set_encoding(int argc, VALUE *argv, VALUE io)
{
rb_io_t *fptr;
VALUE v1, v2, opt;
if (!RB_TYPE_P(io, T_FILE)) {
return rb_funcall2(io, id_set_encoding, argc, argv);
}
argc = rb_scan_args(argc, argv, "11:", &v1, &v2, &opt);
GetOpenFile(io, fptr);
io_encoding_set(fptr, v1, v2, opt);
return io;
}
Returns status information for ios as an object of type
File::Stat.
f = File.new("testfile") s = f.stat "%o" % s.mode #=> "100644" s.blksize #=> 4096 s.atime #=> Wed Apr 09 08:53:54 CDT 2003
static VALUE
rb_io_stat(VALUE obj)
{
rb_io_t *fptr;
struct stat st;
GetOpenFile(obj, fptr);
if (fstat(fptr->fd, &st) == -1) {
rb_sys_fail_path(fptr->pathv);
}
return stat_new(&st);
}
Returns the current “sync mode'' of ios. When sync mode is
true, all output is immediately flushed to the underlying operating system
and is not buffered by Ruby internally. See also IO#fsync.
f = File.new("testfile") f.sync #=> false
static VALUE
rb_io_sync(VALUE io)
{
rb_io_t *fptr;
io = GetWriteIO(io);
GetOpenFile(io, fptr);
return (fptr->mode & FMODE_SYNC) ? Qtrue : Qfalse;
}
Sets the “sync mode'' to true or false.
When sync mode is true, all output is immediately flushed to the underlying
operating system and is not buffered internally. Returns the new state. See
also IO#fsync.
f = File.new("testfile") f.sync = true
(produces no output)
static VALUE
rb_io_set_sync(VALUE io, VALUE sync)
{
rb_io_t *fptr;
io = GetWriteIO(io);
GetOpenFile(io, fptr);
if (RTEST(sync)) {
fptr->mode |= FMODE_SYNC;
}
else {
fptr->mode &= ~FMODE_SYNC;
}
return sync;
}
Reads maxlen bytes from ios using a low-level read and
returns them as a string. Do not mix with other methods that read from
ios or you may get unpredictable results. If the optional
outbuf argument is present, it must reference a String, which will
receive the data. The outbuf will contain only the received data
after the method call even if it is not empty at the beginning. Raises
SystemCallError on error and EOFError at end of
file.
f = File.new("testfile") f.sysread(16) #=> "This is line one"
static VALUE
rb_io_sysread(int argc, VALUE *argv, VALUE io)
{
VALUE len, str;
rb_io_t *fptr;
long n, ilen;
struct read_internal_arg arg;
rb_scan_args(argc, argv, "11", &len, &str);
ilen = NUM2LONG(len);
io_setstrbuf(&str,ilen);
if (ilen == 0) return str;
GetOpenFile(io, fptr);
rb_io_check_byte_readable(fptr);
if (READ_DATA_BUFFERED(fptr)) {
rb_raise(rb_eIOError, "sysread for buffered IO");
}
n = fptr->fd;
/*
* FIXME: removing rb_thread_wait_fd() here changes sysread semantics
* on non-blocking IOs. However, it's still currently possible
* for sysread to raise Errno::EAGAIN if another thread read()s
* the IO after we return from rb_thread_wait_fd() but before
* we call read()
*/
rb_thread_wait_fd(fptr->fd);
rb_io_check_closed(fptr);
io_setstrbuf(&str, ilen);
rb_str_locktmp(str);
arg.fd = fptr->fd;
arg.str_ptr = RSTRING_PTR(str);
arg.len = ilen;
rb_ensure(read_internal_call, (VALUE)&arg, rb_str_unlocktmp, str);
n = arg.len;
if (n == -1) {
rb_sys_fail_path(fptr->pathv);
}
io_set_read_length(str, n);
if (n == 0 && ilen > 0) {
rb_eof_error();
}
OBJ_TAINT(str);
return str;
}
Seeks to a given offset in the stream according to the value of
whence (see IO#seek for values of whence).
Returns the new offset into the file.
f = File.new("testfile") f.sysseek(-13, IO::SEEK_END) #=> 53 f.sysread(10) #=> "And so on."
static VALUE
rb_io_sysseek(int argc, VALUE *argv, VALUE io)
{
VALUE offset, ptrname;
int whence = SEEK_SET;
rb_io_t *fptr;
off_t pos;
if (rb_scan_args(argc, argv, "11", &offset, &ptrname) == 2) {
whence = NUM2INT(ptrname);
}
pos = NUM2OFFT(offset);
GetOpenFile(io, fptr);
if ((fptr->mode & FMODE_READABLE) &&
(READ_DATA_BUFFERED(fptr) || READ_CHAR_PENDING(fptr))) {
rb_raise(rb_eIOError, "sysseek for buffered IO");
}
if ((fptr->mode & FMODE_WRITABLE) && fptr->wbuf.len) {
rb_warn("sysseek for buffered IO");
}
errno = 0;
pos = lseek(fptr->fd, pos, whence);
if (pos == -1 && errno) rb_sys_fail_path(fptr->pathv);
return OFFT2NUM(pos);
}
Writes the given string to ios using a low-level write. Returns
the number of bytes written. Do not mix with other methods that write to
ios or you may get unpredictable results. Raises
SystemCallError on error.
f = File.new("out", "w") f.syswrite("ABCDEF") #=> 6
static VALUE
rb_io_syswrite(VALUE io, VALUE str)
{
rb_io_t *fptr;
long n;
rb_secure(4);
if (!RB_TYPE_P(str, T_STRING))
str = rb_obj_as_string(str);
io = GetWriteIO(io);
GetOpenFile(io, fptr);
rb_io_check_writable(fptr);
str = rb_str_new_frozen(str);
if (fptr->wbuf.len) {
rb_warn("syswrite for buffered IO");
}
n = rb_write_internal(fptr->fd, RSTRING_PTR(str), RSTRING_LEN(str));
RB_GC_GUARD(str);
if (n == -1) rb_sys_fail_path(fptr->pathv);
return LONG2FIX(n);
}
Returns the current offset (in bytes) of ios.
f = File.new("testfile") f.pos #=> 0 f.gets #=> "This is line one\n" f.pos #=> 17
static VALUE
rb_io_tell(VALUE io)
{
rb_io_t *fptr;
off_t pos;
GetOpenFile(io, fptr);
pos = io_tell(fptr);
if (pos < 0 && errno) rb_sys_fail_path(fptr->pathv);
pos -= fptr->rbuf.len;
return OFFT2NUM(pos);
}
Returns ios.
static VALUE
rb_io_to_io(VALUE io)
{
return io;
}
Returns true if ios is associated with a terminal
device (tty), false otherwise.
File.new("testfile").isatty #=> false File.new("/dev/tty").isatty #=> true
static VALUE
rb_io_isatty(VALUE io)
{
rb_io_t *fptr;
GetOpenFile(io, fptr);
if (isatty(fptr->fd) == 0)
return Qfalse;
return Qtrue;
}
Pushes back bytes (passed as a parameter) onto ios, such that a
subsequent buffered read will return it. Only one byte may be pushed back
before a subsequent read operation (that is, you will be able to read only
the last of several bytes that have been pushed back). Has no effect with
unbuffered reads (such as IO#sysread).
f = File.new("testfile") #=> #<File:testfile> b = f.getbyte #=> 0x38 f.ungetbyte(b) #=> nil f.getbyte #=> 0x38
VALUE
rb_io_ungetbyte(VALUE io, VALUE b)
{
rb_io_t *fptr;
GetOpenFile(io, fptr);
rb_io_check_byte_readable(fptr);
if (NIL_P(b)) return Qnil;
if (FIXNUM_P(b)) {
char cc = FIX2INT(b);
b = rb_str_new(&cc, 1);
}
else {
SafeStringValue(b);
}
io_ungetbyte(b, fptr);
return Qnil;
}
Pushes back one character (passed as a parameter) onto ios, such
that a subsequent buffered character read will return it. Only one
character may be pushed back before a subsequent read operation (that is,
you will be able to read only the last of several characters that have been
pushed back). Has no effect with unbuffered reads (such as
IO#sysread).
f = File.new("testfile") #=> #<File:testfile> c = f.getc #=> "8" f.ungetc(c) #=> nil f.getc #=> "8"
VALUE
rb_io_ungetc(VALUE io, VALUE c)
{
rb_io_t *fptr;
long len;
GetOpenFile(io, fptr);
rb_io_check_char_readable(fptr);
if (NIL_P(c)) return Qnil;
if (FIXNUM_P(c)) {
c = rb_enc_uint_chr(FIX2UINT(c), io_read_encoding(fptr));
}
else if (RB_TYPE_P(c, T_BIGNUM)) {
c = rb_enc_uint_chr(NUM2UINT(c), io_read_encoding(fptr));
}
else {
SafeStringValue(c);
}
if (NEED_READCONV(fptr)) {
SET_BINARY_MODE(fptr);
len = RSTRING_LEN(c);
#if SIZEOF_LONG > SIZEOF_INT
if (len > INT_MAX)
rb_raise(rb_eIOError, "ungetc failed");
#endif
make_readconv(fptr, (int)len);
if (fptr->cbuf.capa - fptr->cbuf.len < len)
rb_raise(rb_eIOError, "ungetc failed");
if (fptr->cbuf.off < len) {
MEMMOVE(fptr->cbuf.ptr+fptr->cbuf.capa-fptr->cbuf.len,
fptr->cbuf.ptr+fptr->cbuf.off,
char, fptr->cbuf.len);
fptr->cbuf.off = fptr->cbuf.capa-fptr->cbuf.len;
}
fptr->cbuf.off -= (int)len;
fptr->cbuf.len += (int)len;
MEMMOVE(fptr->cbuf.ptr+fptr->cbuf.off, RSTRING_PTR(c), char, len);
}
else {
NEED_NEWLINE_DECORATOR_ON_READ_CHECK(fptr);
io_ungetbyte(c, fptr);
}
return Qnil;
}
Waits until input is available or times out and returns self or nil when EOF is reached.
static VALUE
io_wait_readable(int argc, VALUE *argv, VALUE io)
{
rb_io_t *fptr;
int i;
ioctl_arg n;
VALUE timeout;
struct timeval timerec;
struct timeval *tv;
GetOpenFile(io, fptr);
rb_io_check_readable(fptr);
rb_scan_args(argc, argv, "01", &timeout);
if (NIL_P(timeout)) {
tv = NULL;
}
else {
timerec = rb_time_interval(timeout);
tv = &timerec;
}
if (rb_io_read_pending(fptr)) return Qtrue;
if (!FIONREAD_POSSIBLE_P(fptr->fd)) return Qfalse;
i = rb_wait_for_single_fd(fptr->fd, RB_WAITFD_IN, tv);
if (i < 0)
rb_sys_fail(0);
rb_io_check_closed(fptr);
if (ioctl(fptr->fd, FIONREAD, &n)) rb_sys_fail(0);
if (n > 0) return io;
return Qnil;
}
Waits until input is available or times out and returns self or nil when EOF is reached.
static VALUE
io_wait_readable(int argc, VALUE *argv, VALUE io)
{
rb_io_t *fptr;
int i;
ioctl_arg n;
VALUE timeout;
struct timeval timerec;
struct timeval *tv;
GetOpenFile(io, fptr);
rb_io_check_readable(fptr);
rb_scan_args(argc, argv, "01", &timeout);
if (NIL_P(timeout)) {
tv = NULL;
}
else {
timerec = rb_time_interval(timeout);
tv = &timerec;
}
if (rb_io_read_pending(fptr)) return Qtrue;
if (!FIONREAD_POSSIBLE_P(fptr->fd)) return Qfalse;
i = rb_wait_for_single_fd(fptr->fd, RB_WAITFD_IN, tv);
if (i < 0)
rb_sys_fail(0);
rb_io_check_closed(fptr);
if (ioctl(fptr->fd, FIONREAD, &n)) rb_sys_fail(0);
if (n > 0) return io;
return Qnil;
}
Waits until IO writable is available or times out and returns self or nil when EOF is reached.
static VALUE
io_wait_writable(int argc, VALUE *argv, VALUE io)
{
rb_io_t *fptr;
int i;
VALUE timeout;
struct timeval timerec;
struct timeval *tv;
GetOpenFile(io, fptr);
rb_io_check_writable(fptr);
rb_scan_args(argc, argv, "01", &timeout);
if (NIL_P(timeout)) {
tv = NULL;
}
else {
timerec = rb_time_interval(timeout);
tv = &timerec;
}
i = rb_wait_for_single_fd(fptr->fd, RB_WAITFD_OUT, tv);
if (i < 0)
rb_sys_fail(0);
rb_io_check_closed(fptr);
if (i & RB_WAITFD_OUT)
return io;
return Qnil;
}
Returns console size.
You must require 'io/console' to use this method.
static VALUE
console_winsize(VALUE io)
{
rb_io_t *fptr;
int fd;
rb_console_size_t ws;
GetOpenFile(io, fptr);
fd = GetWriteFD(fptr);
if (!getwinsize(fd, &ws)) rb_sys_fail(0);
return rb_assoc_new(INT2NUM(winsize_row(&ws)), INT2NUM(winsize_col(&ws)));
}
Tries to set console size. The effect depends on the platform and the running environment.
You must require 'io/console' to use this method.
static VALUE
console_set_winsize(VALUE io, VALUE size)
{
rb_io_t *fptr;
rb_console_size_t ws;
#if defined _WIN32
HANDLE wh;
int newrow, newcol;
#endif
VALUE row, col, xpixel, ypixel;
#if defined TIOCSWINSZ
int fd;
#endif
GetOpenFile(io, fptr);
size = rb_Array(size);
rb_scan_args((int)RARRAY_LEN(size), RARRAY_PTR(size), "22",
&row, &col, &xpixel, &ypixel);
#if defined TIOCSWINSZ
fd = GetWriteFD(fptr);
ws.ws_row = ws.ws_col = ws.ws_xpixel = ws.ws_ypixel = 0;
#define SET(m) ws.ws_##m = NIL_P(m) ? 0 : (unsigned short)NUM2UINT(m)
SET(row);
SET(col);
SET(xpixel);
SET(ypixel);
#undef SET
if (!setwinsize(fd, &ws)) rb_sys_fail(0);
#elif defined _WIN32
wh = (HANDLE)rb_w32_get_osfhandle(GetReadFD(fptr));
newrow = (SHORT)NUM2UINT(row);
newcol = (SHORT)NUM2UINT(col);
if (!getwinsize(GetReadFD(fptr), &ws)) {
rb_sys_fail("GetConsoleScreenBufferInfo");
}
if ((ws.dwSize.X < newcol && (ws.dwSize.X = newcol, 1)) ||
(ws.dwSize.Y < newrow && (ws.dwSize.Y = newrow, 1))) {
if (!(SetConsoleScreenBufferSize(wh, ws.dwSize) || SET_LAST_ERROR)) {
rb_sys_fail("SetConsoleScreenBufferInfo");
}
}
ws.srWindow.Left = 0;
ws.srWindow.Top = 0;
ws.srWindow.Right = newcol;
ws.srWindow.Bottom = newrow;
if (!(SetConsoleWindowInfo(wh, FALSE, &ws.srWindow) || SET_LAST_ERROR)) {
rb_sys_fail("SetConsoleWindowInfo");
}
#endif
return io;
}
Writes the given string to ios. The stream must be opened for
writing. If the argument is not a string, it will be converted to a string
using to_s. Returns the number of bytes written.
count = $stdout.write("This is a test\n") puts "That was #{count} bytes of data"
produces:
This is a test That was 15 bytes of data
static VALUE
io_write_m(VALUE io, VALUE str)
{
return io_write(io, str, 0);
}
Writes the given string to ios using the write(2) system call after O_NONBLOCK is set for the underlying file descriptor.
It returns the number of bytes written.
#write_nonblock just calls the write(2) system call. It causes all errors the write(2) system call causes: Errno::EWOULDBLOCK, Errno::EINTR, etc. The result may also be smaller than string.length (partial write). The caller should care such errors and partial write.
If the exception is Errno::EWOULDBLOCK or Errno::AGAIN, it is extended by IO::WaitWritable. So IO::WaitWritable can be used to rescue the exceptions for retrying write_nonblock.
# Creates a pipe. r, w = IO.pipe # write_nonblock writes only 65536 bytes and return 65536. # (The pipe size is 65536 bytes on this environment.) s = "a" * 100000 p w.write_nonblock(s) #=> 65536 # write_nonblock cannot write a byte and raise EWOULDBLOCK (EAGAIN). p w.write_nonblock("b") # Resource temporarily unavailable (Errno::EAGAIN)
If the write buffer is not empty, it is flushed at first.
When #write_nonblock raises an exception kind of IO::WaitWritable, #write_nonblock should not be called until io is writable for avoiding busy loop. This can be done as follows.
begin result = io.write_nonblock(string) rescue IO::WaitWritable, Errno::EINTR IO.select(nil, [io]) retry end
Note that this doesn't guarantee to write all data in string. The length written is reported as result and it should be checked later.
On some platforms such as Windows, #write_nonblock is not supported
according to the kind of the IO object. In such
cases, #write_nonblock raises
Errno::EBADF.
static VALUE
rb_io_write_nonblock(VALUE io, VALUE str)
{
rb_io_t *fptr;
long n;
rb_secure(4);
if (!RB_TYPE_P(str, T_STRING))
str = rb_obj_as_string(str);
io = GetWriteIO(io);
GetOpenFile(io, fptr);
rb_io_check_writable(fptr);
if (io_fflush(fptr) < 0)
rb_sys_fail(0);
rb_io_set_nonblock(fptr);
n = write(fptr->fd, RSTRING_PTR(str), RSTRING_LEN(str));
if (n == -1) {
if (errno == EWOULDBLOCK || errno == EAGAIN)
rb_mod_sys_fail(rb_mWaitWritable, "write would block");
rb_sys_fail_path(fptr->pathv);
}
return LONG2FIX(n);
}
Private Instance Methods
# File lib/scanf.rb, line 677 def block_scanf(str) final = [] # Sub-ideal, since another FS gets created in scanf. # But used here to determine the number of specifiers. fstr = Scanf::FormatString.new(str) last_spec = fstr.last_spec begin current = scanf(str) break if current.empty? final.push(yield(current)) end until eof || fstr.last_spec_tried == last_spec return final end
# File lib/scanf.rb, line 668 def soak_up_spaces c = getc ungetc(c) if c until eof ||! c || /\S/.match(c.chr) c = getc end ungetc(c) if (c && /\S/.match(c.chr)) end