'\" te
.\" Copyright 1989 AT&T.  Copyright (c) 2005, Sun Microsystems, Inc.  All Rights Reserved.
.\" The contents of this file are subject to the terms of the Common Development and Distribution License (the "License").  You may not use this file except in compliance with the License. You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE or http://www.opensolaris.org/os/licensing.
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.TH assert 3C "30 Mar 2005" "SunOS 5.11" "Standard C Library Functions"
.SH NAME
assert \- verify program assertion
.SH SYNOPSIS
.LP
.nf
#include <assert.h>

\fBvoid\fR \fBassert\fR(\fBint\fR \fIexpression\fR);
.fi

.SH DESCRIPTION
.sp
.LP
The \fBassert()\fR macro inserts diagnostics into applications. When executed,
if \fIexpression\fR is \fBFALSE\fR (zero), \fBassert()\fR prints the error
message
.sp
.in +2
.nf
Assertion failed: \fIexpression\fR, file \fIxyz\fR, line \fInnn\fR
.fi
.in -2

.sp
.LP
on the standard error output and aborts. In the error message, \fIxyz\fR is the
name of the source file and \fInnn\fR the source line number of the
\fBassert()\fR statement. These are respectively the values of the preprocessor
macros \fB__FILE__\fR and \fB__LINE__\fR.
.sp
.LP
Since \fBassert()\fR is implemented as a macro, the \fIexpression\fR may not
contain any string literals.
.sp
.LP
Compiling with the preprocessor option \fB\fR\fB-DNDEBUG\fR or with the
preprocessor control statement \fB#define NDEBUG\fR ahead of the \fB#include\fR
<\fBassert.h\fR> statement, will stop assertions from being compiled into the
program.
.sp
.LP
Messages printed from this function are in the native language specified by the
\fBLC_MESSAGES\fR locale category. See \fBsetlocale\fR(3C).
.SH ATTRIBUTES
.sp
.LP
See \fBattributes\fR(5) for descriptions of the following attributes:
.sp

.sp
.TS
tab() box;
cw(2.75i) |cw(2.75i) 
lw(2.75i) |lw(2.75i) 
.
ATTRIBUTE TYPEATTRIBUTE VALUE
_
Interface StabilityCommitted
_
MT-LevelSafe
_
StandardSee \fBstandards\fR(5).
.TE

.SH SEE ALSO
.sp
.LP
\fBabort\fR(3C), \fBgettext\fR(3C), \fBsetlocale\fR(3C), \fBattributes\fR(5),
\fBstandards\fR(5)