1.\" $NetBSD: assert.3,v 1.14 2016/06/01 01:31:11 pgoyette Exp $ 2.\" 3.\" Copyright (c) 1991, 1993 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. Neither the name of the University nor the names of its contributors 15.\" may be used to endorse or promote products derived from this software 16.\" without specific prior written permission. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 19.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 22.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28.\" SUCH DAMAGE. 29.\" 30.\" @(#)assert.3 8.1 (Berkeley) 6/9/93 31.\" 32.Dd June 1, 2016 33.Dt ASSERT 3 34.Os 35.Sh NAME 36.Nm assert 37.Nd expression verification macro 38.Sh SYNOPSIS 39.In assert.h 40.Fn assert expression 41.Sh DESCRIPTION 42The 43.Fn assert 44macro tests the given 45.Ar expression 46and if it is false, 47the calling process is terminated. 48A diagnostic message, consisting of the text of the expression, 49the name of the source file, the line number and the enclosing 50function, 51is written to 52.Em stderr 53and the 54.Xr abort 3 55function is 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.Xr cc 1 70option 71.Fl DNDEBUG . 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, function \e"%s\e"\en", \e 80 "expression", __FILE__, __LINE__, __func__); 81.Ed 82.Sh SEE ALSO 83.Xr cc 1 , 84.Xr _DIAGASSERT 3 , 85.Xr abort 3 86.Sh STANDARDS 87The 88.Fn assert 89macro conforms to 90.St -isoC-99 . 91.Sh HISTORY 92A 93.Nm 94macro appeared in 95.At v7 . 96.Pp 97Information on the name of the enclosing function appeared in 98.St -isoC-99 . 99