Originální popis anglicky:
realloc - memory reallocator
Návod, kniha: POSIX Programmer's Manual
#include <stdlib.h>
void *realloc(void *
ptr, size_t
size);
The
realloc() function shall change the size of the memory object pointed
to by
ptr to the size specified by
size. The contents of the
object shall remain unchanged up to the lesser of the new and old sizes. If
the new size of the memory object would require movement of the object, the
space for the previous instantiation of the object is freed. If the new size
is larger, the contents of the newly allocated portion of the object are
unspecified. If
size is 0 and
ptr is not a null pointer, the
object pointed to is freed. If the space cannot be allocated, the object shall
remain unchanged.
If
ptr is a null pointer,
realloc() shall be equivalent to
malloc() for the specified size.
If
ptr does not match a pointer returned earlier by
calloc(),
malloc(), or
realloc() or if the space has previously been
deallocated by a call to
free() or
realloc(), the behavior is
undefined.
The order and contiguity of storage allocated by successive calls to
realloc() is unspecified. The pointer returned if the allocation
succeeds shall be suitably aligned so that it may be assigned to a pointer to
any type of object and then used to access such an object in the space
allocated (until the space is explicitly freed or reallocated). Each such
allocation shall yield a pointer to an object disjoint from any other object.
The pointer returned shall point to the start (lowest byte address) of the
allocated space. If the space cannot be allocated, a null pointer shall be
returned.
Upon successful completion with a size not equal to 0,
realloc() shall
return a pointer to the (possibly moved) allocated space. If
size is 0,
either a null pointer or a unique pointer that can be successfully passed to
free() shall be returned. If there is not enough available memory,
realloc() shall return a null pointer and set
errno to
[ENOMEM].
The
realloc() function shall fail if:
- ENOMEM
- Insufficient memory is available.
The following sections are informative.
None.
None.
None.
None.
calloc() ,
free() ,
malloc() , the Base Definitions volume
of IEEE Std 1003.1-2001,
<stdlib.h>
Portions of this text are reprinted and reproduced in electronic form from IEEE
Std 1003.1, 2003 Edition, Standard for Information Technology -- Portable
Operating System Interface (POSIX), The Open Group Base Specifications Issue
6, Copyright (C) 2001-2003 by the Institute of Electrical and Electronics
Engineers, Inc and The Open Group. In the event of any discrepancy between
this version and the original IEEE and The Open Group Standard, the original
IEEE and The Open Group Standard is the referee document. The original
Standard can be obtained online at http://www.opengroup.org/unix/online.html
.
