class SystemCallError

SystemCallError is the base class for all low-level platform-dependent errors.

The errors available on the current platform are subclasses of SystemCallError and are defined in the Errno module."does/not/exist")

raises the exception:

Errno::ENOENT: No such file or directory - does/not/exist

Public Class Methods

system_call_error === other → true or false click to toggle source

Return true if the receiver is a generic SystemCallError, or if the error numbers self and other are the same.

static VALUE
syserr_eqq(VALUE self, VALUE exc)
    VALUE num, e;
    ID en;

    CONST_ID(en, "errno");

    if (!rb_obj_is_kind_of(exc, rb_eSystemCallError)) {
        if (!rb_respond_to(exc, en)) return Qfalse;
    else if (self == rb_eSystemCallError) return Qtrue;

    num = rb_attr_get(exc, rb_intern("errno"));
    if (NIL_P(num)) {
        num = rb_funcall(exc, en, 0, 0);
    e = rb_const_get(self, rb_intern("Errno"));
    if (FIXNUM_P(num) ? num == e : rb_equal(num, e))
        return Qtrue;
    return Qfalse;
new(msg, errno) → system_call_error_subclass click to toggle source

If errno corresponds to a known system error code, constructs the appropriate Errno class for that error, otherwise constructs a generic SystemCallError object. The error number is subsequently available via the errno method.

static VALUE
syserr_initialize(int argc, VALUE *argv, VALUE self)
#if !defined(_WIN32)
    char *strerror();
    const char *err;
    VALUE mesg, error;
    VALUE klass = rb_obj_class(self);

    if (klass == rb_eSystemCallError) {
        st_data_t data = (st_data_t)klass;
        rb_scan_args(argc, argv, "11", &mesg, &error);
        if (argc == 1 && FIXNUM_P(mesg)) {
            error = mesg; mesg = Qnil;
        if (!NIL_P(error) && st_lookup(syserr_tbl, NUM2LONG(error), &data)) {
            klass = (VALUE)data;
            /* change class */
            if (!RB_TYPE_P(self, T_OBJECT)) { /* insurance to avoid type crash */
                rb_raise(rb_eTypeError, "invalid instance type");
            RBASIC(self)->klass = klass;
    else {
        rb_scan_args(argc, argv, "01", &mesg);
        error = rb_const_get(klass, rb_intern("Errno"));
    if (!NIL_P(error)) err = strerror(NUM2INT(error));
    else err = "unknown error";
    if (!NIL_P(mesg)) {
        rb_encoding *le = rb_locale_encoding();
        VALUE str = StringValue(mesg);
        rb_encoding *me = rb_enc_get(mesg);

        mesg = rb_sprintf("%s - %"PRIsVALUE, err, mesg);
        if (le != me && rb_enc_asciicompat(me)) {
            le = me;
        }/* else assume err is non ASCII string. */
        OBJ_INFECT(mesg, str);
        rb_enc_associate(mesg, le);
    else {
        mesg = rb_str_new2(err);
        rb_enc_associate(mesg, rb_locale_encoding());
    rb_call_super(1, &mesg);
    rb_iv_set(self, "errno", error);
    return self;

Public Instance Methods

errno → fixnum click to toggle source

Return this SystemCallError's error number.

static VALUE
syserr_errno(VALUE self)
    return rb_attr_get(self, rb_intern("errno"));