1.\" Copyright (c) 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" @(#)assert.3 8.1 (Berkeley) 6/9/93 33.\" 34.Dd June 9, 1993 35.Dt ASSERT 3 36.Os 37.Sh NAME 38.Nm assert 39.Nd expression verification macro 40.Sh SYNOPSIS 41.Fd #include <assert.h> 42.Fn assert expression 43.Sh DESCRIPTION 44The 45.Fn assert 46macro tests the given 47.Ar expression 48and if it is false, 49the calling process is terminated. 50A 51diagnostic message is written to the 52.Em stderr 53and the function 54.Xr abort 3 55is called effectively terminating the program. 56.Pp 57If 58.Ar expression 59is true, 60the 61.Fn assert 62macro does nothing. 63.Pp 64The 65.Fn assert 66macro 67may be removed at compile time with 68the 69.Fl NDEBUG 70option, see 71.Xr cc 1 . 72.Sh DIAGNOSTICS 73The following diagnostic message is written to 74.Em stderr 75if 76.Ar expression 77is false: 78.Bd -literal -offset indent 79"assertion \e"%s\e" failed: file \e"%s\e", line %d\n", \e 80 "expression", __FILE__, __LINE__); 81.Ed 82.Sh HISTORY 83A 84.Nm assert 85macro appeared in 86.At v6 . 87