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.\"   Copyright (c) 1994-2006 Lars Wirzenius.  All rights reserved.
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.\" part of publib
.\" "@(#)publib-alloc:$Id: xmalloc.3,v 1.5 1998/10/25 20:48:38 liw Exp $"
.\"
.TH XMALLOC 3pub "C Programmer's Manual" "Publib" "C Programmer's Manual"
.SH NAME
xmalloc, xrealloc, xfree, xstrdup, xmemdup, memdup \- memory 
allocation functions for Publib
.SH SYNOPSIS
#include <publib.h>
.sp 1
.nf
void *\fBxmalloc\fR(size_t \fIbytes\fR);
void *\fBxrealloc\fR(void *\fIptr\fR, size_t \fIbytes\fR);
void \fBxfree\fR(void *\fIptr\fR);
char *\fBxstrdup\fR(const char *\fIstring\fR);
void *\fBmemdup\fR(const void *\fImem\fR, size_t \fIbytes\fR);
void *\fBxmemdup\fR(const void *\fImem\fR, size_t \fIbytes\fR);
.SH "DESCRIPTION"
These functions are utility functions for memory allocation from the
publib library.  \fIxmalloc\fR, \fIxrealloc\fR, and \fIxfree\fR are
error checking versions of the standard library routines \fImalloc\fR,
\fIrealloc\fR, and \fIfree\fR, respectively.  They are guaranteed to
never return unless there was no problem: if, for example,
\fIxmalloc\fR is unable to allocate the requested amount of memory, it
prints an error message and terminates the program.  Hence, the caller
does not need to check for a NULL return value, and the code that
calls these functions is simpler due to the lack of error checks.
.PP
Similarly, \fIxstrdup\fR is an error checking version of the common
(though not standard) \fIstrdup\fR routine, which creates a duplicate
of a string by allocating memory for the copy with \fImalloc\fR.  (For
systems that lack \fIstrdup\fR, publib provides one in its portability
module; it is always declared in <publib.h>.)
.PP
\fImemdup\fR is similar to \fIstrdup\fR, it creates a copy of an
arbitrary memory area (the arguments are a pointer to the beginning of
the area, and its size) by allocating memory for the copy with
\fImalloc\fR.  \fIxmemdup\fR is its error checking version.
.SH NOTE
\fIxmalloc\fR and \fIxrealloc\fR treat a request to allocate a block
of 0 bytes as an error.
\fIxrealloc\fR will allow its first argument to be NULL.
.SH "SEE ALSO"
publib(3), malloc(3), strdup(3)
.SH AUTHOR
Lars Wirzenius (lars.wirzenius@helsinki.fi)