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Declares ruby_xmalloc().
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Declares ruby_xmalloc().
- Author
- Ruby developers ruby-.nosp@m.core.nosp@m.@ruby.nosp@m.-lan.nosp@m.g.org
- Copyright
- This file is a part of the programming language Ruby. Permission is hereby granted, to either redistribute and/or modify this file, provided that the conditions mentioned in the file COPYING are met. Consult the file for details.
- Warning
- Symbols prefixed with either
RBIMPL
or rbimpl
are implementation details. Don't take them as canon. They could rapidly appear then vanish. The name (path) of this header file is also an implementation detail. Do not expect it to persist at the place it is now. Developers are free to move it anywhere anytime at will.
- Note
- To ruby-core: remember that this header can be possibly recursively included from extension libraries written in C++. Do not expect for instance
__VA_ARGS__
is always available. We assume C99 for ruby itself but we don't assume languages of extension libraries. They could be written in C++98.
Definition in file xmalloc.h.
◆ USE_GC_MALLOC_OBJ_INFO_DETAILS
#define USE_GC_MALLOC_OBJ_INFO_DETAILS 0 |
- Warning
- Do not touch this macro.
-
It is an implementation detail.
-
It was a failure at the first place to let you know about it.
-
The value of this macro must match for ruby itself and all extension libraries, otherwise serious memory corruption shall occur.
Definition at line 50 of file xmalloc.h.
◆ ruby_xcalloc()
void* ruby_xcalloc |
( |
size_t |
nelems, |
|
|
size_t |
elemsiz |
|
) |
| |
Identical to ruby_xmalloc2(), except it returns a zero-filled storage instance.
It can also be seen as a routine identical to ruby_xmalloc(), except it calls calloc() instead of malloc().
- Parameters
-
[in] | nelems | Number of elements. |
[in] | elemsiz | Size of an element. |
- Exceptions
-
rb_eNoMemError | No space left for allocation. |
rb_eArgError | nelems * elemsiz would overflow. |
- Returns
- A valid pointer to an allocated storage instance; which has at least
nelems
* elemsiz
bytes width, with appropriate alignment detected by the underlying calloc() routine.
- Postcondition
- The returned storage instance is filled with zeros.
- Note
- It doesn't return NULL.
-
Unlike some calloc() implementations, it allocates something and returns a meaningful value even when
nelems
or elemsiz
or both are zero.
- Warning
- The return value shall be invalidated exactly once by either ruby_xfree(), ruby_xrealloc(), or ruby_xrealloc2(). It is a failure to pass it to system free(), because the system and Ruby might or might not share the same malloc() implementation.
Definition at line 4512 of file gc.c.
◆ ruby_xfree()
void ruby_xfree |
( |
void * |
ptr | ) |
|
Deallocates a storage instance.
- Parameters
-
[out] | ptr | Either
- NULL, or
- a valid pointer previously returned from one of:
|
- Precondition
- The passed pointer must point to a valid live storage instance. It is a failure to pass an already freed pointer.
- Postcondition
- The storage instance pointed by the passed pointer gets invalidated; it is no longer addressable.
- Warning
- Every single storage instance that was previously allocated by either ruby_xmalloc(), ruby_xmalloc2(), ruby_xcalloc(), ruby_xrealloc(), or ruby_xrealloc2() shall be invalidated exactly once by either passing it to ruby_xfree(), or passing it to either ruby_xrealloc(), ruby_xrealloc2() then check the return value for invalidation.
-
Do not pass anything other than pointers described above. For instance pointers returned from malloc() or mmap() shall not be passed to this function, because the underlying memory management mechanism could differ.
-
Do not pass any invalid pointers to this function e.g. by calling it twice with a same argument.
Definition at line 4594 of file gc.c.
Referenced by rb_str_resize().
◆ ruby_xmalloc()
void* ruby_xmalloc |
( |
size_t |
size | ) |
|
Allocates a storage instance.
It is largely the same as system malloc(), except:
- It raises Ruby exceptions instead of returning NULL, and
- In case of
ENOMEM
it tries to GC to make some room.
- Parameters
-
[in] | size | Requested amount of memory. |
- Exceptions
-
rb_eNoMemError | No space left for size bytes allocation. |
- Returns
- A valid pointer to an allocated storage instance; which has at least
size
bytes width, with appropriate alignment detected by the underlying malloc() routine.
- Note
- It doesn't return NULL.
-
Unlike some malloc() implementations, it allocates something and returns a meaningful value even when
size
is equal to zero.
- Warning
- The return value shall be invalidated exactly once by either ruby_xfree(), ruby_xrealloc(), or ruby_xrealloc2(). It is a failure to pass it to system free(), because the system and Ruby might or might not share the same malloc() implementation.
Definition at line 4472 of file gc.c.
◆ ruby_xmalloc2()
void* ruby_xmalloc2 |
( |
size_t |
nelems, |
|
|
size_t |
elemsiz |
|
) |
| |
Identical to ruby_xmalloc(), except it allocates nelems
* elemsiz
bytes.
This is needed because the multiplication could integer overflow. On such situations Ruby does not try to allocate at all but raises Ruby level exceptions instead. If there is no integer overflow the behaviour is exactly the same as ruby_xmalloc(nelems*elemsiz)
.
- Parameters
-
[in] | nelems | Number of elements. |
[in] | elemsiz | Size of an element. |
- Exceptions
-
rb_eNoMemError | No space left for allocation. |
rb_eArgError | nelems * elemsiz would overflow. |
- Returns
- A valid pointer to an allocated storage instance; which has at least
nelems
* elemsiz
bytes width, with appropriate alignment detected by the underlying malloc() routine.
- Note
- It doesn't return NULL.
-
Unlike some malloc() implementations, it allocates something and returns a meaningful value even when
nelems
or elemsiz
or both are zero.
- Warning
- The return value shall be invalidated exactly once by either ruby_xfree(), ruby_xrealloc(), or ruby_xrealloc2(). It is a failure to pass it to system free(), because the system and Ruby might or might not share the same malloc() implementation.
Definition at line 4498 of file gc.c.
◆ ruby_xrealloc()
void* ruby_xrealloc |
( |
void * |
ptr, |
|
|
size_t |
newsiz |
|
) |
| |
Resize the storage instance.
- Parameters
-
[in] | ptr | A valid pointer to a storage instance that was previously returned from either:
|
[in] | newsiz | Requested new amount of memory. |
- Exceptions
-
rb_eNoMemError | No space left for newsiz bytes allocation. |
- Returns
- A valid pointer to a (possibly newly allocated) storage instance; which has at least
newsiz
bytes width, with appropriate alignment detected by the underlying realloc() routine.
- Precondition
- The passed pointer must point to a valid live storage instance. It is a failure to pass an already freed pointer.
- Postcondition
- In case the function returns the passed pointer as-is, the storage instance that the pointer holds is either grown or shrunken to have at least
newsiz
bytes. Otherwise a valid pointer to a newly allocated storage instance is returned. In this case ptr
is invalidated as if it was passed to ruby_xfree().
- Note
- It doesn't return NULL.
- Warning
- Unlike some realloc() implementations, passing zero to
newsiz
is not the same as calling ruby_xfree(), because this function never returns NULL. Something meaningful still returns then.
-
It is a failure not to check the return value. Do not assume anything on it. It could be either identical to, or distinct form the passed argument.
-
Do not assume anything on the alignment of the return value. There is no guarantee that it inherits the passed argument's one.
-
The return value shall be invalidated exactly once by either ruby_xfree(), ruby_xrealloc(), or ruby_xrealloc2(). It is a failure to pass it to system free(), because the system and Ruby might or might not share the same malloc() implementation.
Definition at line 4545 of file gc.c.
◆ ruby_xrealloc2()
void* ruby_xrealloc2 |
( |
void * |
ptr, |
|
|
size_t |
newelems, |
|
|
size_t |
newsiz |
|
) |
| |
Identical to ruby_xrealloc(), except it resizes the given storage instance to newelems
* newsiz
bytes.
This is needed because the multiplication could integer overflow. On such situations Ruby does not try to touch the contents of argument pointer at all but raises Ruby level exceptions instead. If there is no integer overflow the behaviour is exactly the same as ruby_xrealloc(ptr,nelems*elemsiz)
.
This is roughly the same as reallocarray() function that OpenBSD etc. provides, but also interacts with our GC.
- Parameters
-
[in] | ptr | A valid pointer to a storage instance that was previously returned from either:
|
[in] | newelems | Requested new number of elements. |
[in] | newsiz | Requested new size of each element. |
- Exceptions
-
rb_eNoMemError | No space left for allocation. |
rb_eArgError | newelems * newsiz would overflow. |
- Returns
- A valid pointer to a (possibly newly allocated) storage instance; which has at least
newelems
* newsiz
bytes width, with appropriate alignment detected by the underlying realloc() routine.
- Precondition
- The passed pointer must point to a valid live storage instance. It is a failure to pass an already freed pointer.
- Postcondition
- In case the function returns the passed pointer as-is, the storage instance that the pointer holds is either grown or shrunken to have at least
newelems
* newsiz
bytes. Otherwise a valid pointer to a newly allocated storage instance is returned. In this case ptr
is invalidated as if it was passed to ruby_xfree().
- Note
- It doesn't return NULL.
- Warning
- Unlike some realloc() implementations, passing zero to either
newelems
or elemsiz
are not the same as calling ruby_xfree(), because this function never returns NULL. Something meaningful still returns then.
-
It is a failure not to check the return value. Do not assume anything on it. It could be either identical to, or distinct form the passed argument.
-
Do not assume anything on the alignment of the return value. There is no guarantee that it inherits the passed argument's one.
-
The return value shall be invalidated exactly once by either ruby_xfree(), ruby_xrealloc(), or ruby_xrealloc2(). It is a failure to pass it to system free(), because the system and Ruby might or might not share the same malloc() implementation.
Definition at line 4569 of file gc.c.