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.\"     @(#)malloc.3	8.1 (Berkeley) 6/4/93
.\" $FreeBSD: src/lib/libc/stdlib/malloc.3,v 1.80.2.2.2.1 2010/06/14 02:09:06 kensmith Exp $
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.Dd September 26, 2009
.Dt reallocf 3bsd
.Os
.Sh NAME
.Nm reallocf
.Nd general purpose memory allocation functions
.Sh LIBRARY
.ds str-Lb-libbsd Utility functions from BSD systems (libbsd, \-lbsd)
.ds doc-str-Lb-libbsd \*[str-Lb-libbsd]
.Lb libbsd
.Sh SYNOPSIS
.In stdlib.h
(See
.Xr libbsd 7
for include usage.)
.Ft void *
.Fn reallocf "void *ptr" "size_t size"
.Sh DESCRIPTION
The
.Fn reallocf
function changes the size of the previously allocated memory referenced by
.Fa ptr
to
.Fa size
bytes.
The contents of the memory are unchanged up to the lesser of the new and
old sizes.
If the new size is larger,
the contents of the newly allocated portion of the memory are undefined.
Upon success, the memory referenced by
.Fa ptr
is freed and a pointer to the newly allocated memory is returned.
Note that
.Fn reallocf
may move the memory allocation, resulting in a different return value than
.Fa ptr .
If
.Fa ptr
is
.Dv NULL ,
the
.Fn reallocf
function behaves identically to
.Fn malloc
for the specified size.
Upon failure, when the requested memory cannot be allocated, the passed pointer
is freed to ease the problems with traditional coding styles for
.Fn reallocf
causing memory leaks in libraries.
.Sh RETURN VALUES
The
.Fn reallocf
function returns a pointer, possibly identical to
.Fa ptr ,
to the allocated memory
if successful; otherwise a
.Dv NULL
pointer is returned, and
.Va errno
is set to
.Er ENOMEM
if the error was the result of an allocation failure.
The buffer is deallocated in this case.
.Sh SEE ALSO
.Xr brk 2 ,
.Xr mmap 2 ,
.Xr alloca 3 ,
.Xr calloc 3 ,
.Xr free 3 ,
.Xr malloc 3 ,
.Xr posix_memalign 3 ,
.Xr realloc 3 ,
.Sh HISTORY
The
.Fn reallocf
function first appeared in
.Fx 3.0 .