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realloc(3posix) [linux man page]

REALLOC(P)						     POSIX Programmer's Manual							REALLOC(P)

NAME

       realloc - memory reallocator

SYNOPSIS

       #include <stdlib.h>

       void *realloc(void *ptr, size_t size);

DESCRIPTION

       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  suc-
       ceeds 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 allo-
       cated, a null pointer shall be returned.

RETURN VALUE

       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].

ERRORS

       The realloc() function shall fail if:

       ENOMEM Insufficient memory is available.

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       None.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       calloc() , free() , malloc() , the Base Definitions volume of IEEE Std 1003.1-2001, <stdlib.h>

COPYRIGHT

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technol-
       ogy -- 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 .

IEEE
/The Open Group						       2003								REALLOC(P)

Check Out this Related Man Page

FREE(3P)						     POSIX Programmer's Manual							  FREE(3P)

PROLOG

       This  manual page is part of the POSIX Programmer's Manual.  The Linux implementation of this interface may differ (consult the correspond-
       ing Linux manual page for details of Linux behavior), or the interface may not be implemented on Linux.

NAME

       free - free allocated memory

SYNOPSIS

       #include <stdlib.h>

       void free(void *ptr);

DESCRIPTION

       The free() function shall cause the space pointed to by ptr to be deallocated; that is, made available for further allocation. If ptr is  a
       null  pointer,  no  action  shall  occur.   Otherwise, if the argument does not match a pointer earlier returned by the calloc(), malloc(),
       posix_memalign(),  realloc(), or   strdup()  function, or if the space has been deallocated by a call to free() or realloc(), the  behavior
       is undefined.

       Any use of a pointer that refers to freed space results in undefined behavior.

RETURN VALUE

       The free() function shall not return a value.

ERRORS

       No errors are defined.

       The following sections are informative.

EXAMPLES

       None.

APPLICATION USAGE

       There is now no requirement for the implementation to support the inclusion of <malloc.h>.

RATIONALE

       None.

FUTURE DIRECTIONS

       None.

SEE ALSO

       calloc(), malloc(), realloc(), the Base Definitions volume of IEEE Std 1003.1-2001, <stdlib.h>

COPYRIGHT

       Portions of this text are reprinted and reproduced in electronic form from IEEE Std 1003.1, 2003 Edition, Standard for Information Technol-
       ogy -- 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 .

IEEE
/The Open Group						       2003								  FREE(3P)
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