1.\" $NetBSD: _DIAGASSERT.3,v 1.6 2003/06/27 00:04:34 lukem Exp $ 2.\" 3.\" Copyright (c) 2001 The NetBSD Foundation, Inc. 4.\" All rights reserved. 5.\" 6.\" This code is derived from software contributed to The NetBSD Foundation 7.\" by Luke Mewburn. 8.\" 9.\" Redistribution and use in source and binary forms, with or without 10.\" modification, are permitted provided that the following conditions 11.\" are met: 12.\" 1. Redistributions of source code must retain the above copyright 13.\" notice, this list of conditions and the following disclaimer. 14.\" 2. Redistributions in binary form must reproduce the above copyright 15.\" notice, this list of conditions and the following disclaimer in the 16.\" documentation and/or other materials provided with the distribution. 17.\" 3. All advertising materials mentioning features or use of this software 18.\" must display the following acknowledgement: 19.\" This product includes software developed by the NetBSD 20.\" Foundation, Inc. and its contributors. 21.\" 4. Neither the name of The NetBSD Foundation nor the names of its 22.\" contributors may be used to endorse or promote products derived 23.\" from this software without specific prior written permission. 24.\" 25.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 26.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 27.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 28.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 29.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 30.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 31.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 32.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 33.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 34.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 35.\" POSSIBILITY OF SUCH DAMAGE. 36.\" 37.Dd June 27, 2003 38.Dt _DIAGASSERT 3 39.Os 40.Sh NAME 41.Nm _DIAGASSERT 42.Nd expression verification macro 43.Sh SYNOPSIS 44.In assert.h 45.Fn _DIAGASSERT expression 46.Sh DESCRIPTION 47The 48.Fn _DIAGASSERT 49macro tests the given 50.Ar expression 51and if it is false, one or more of the following may occur: 52.Bl -bullet -offset indent 53.It 54a diagnostic message may be logged to the system logger with 55.Xr syslog 3 . 56This is default behaviour. 57.It 58a diagnostic message may be printed to the 59.Dv stderr 60stream. 61.It 62the calling process will be terminated by calling 63.Xr abort 3 . 64.El 65.Pp 66This behaviour may be changed by setting the 67.Ev LIBC_DIAGASSERT 68environment variable (see below). 69.Pp 70The diagnostic message consists of the text of the expression, 71the name of the source file, the line number and the enclosing 72function. 73.Pp 74If 75.Ar expression 76is true, 77the 78.Fn _DIAGASSERT 79macro does nothing. 80.Pp 81The 82.Fn _DIAGASSERT 83macro is not compiled in by default, and will only be compiled in with the 84.Xr cc 1 85option 86.Fl D_DIAGNOSTIC . 87.Pp 88This macro is used in the various system libraries such as the 89.Lb libc 90to ensure that various library calls are invoked with valid arguments. 91.Sh ENVIRONMENT 92The 93.Ev LIBC_DIAGASSERT 94environment variable can be used to modify the default behaviour of 95logging the assertion to the system logger. 96.Pp 97.Ev LIBC_DIAGASSERT 98may be set to one or more of the following characters: 99.Bl -tag -width xxx -offset indent 100.It a 101.Xr abort 3 102once any assertion messages have been logged and/or printed. 103.It A 104Opposite of 105.Dq a . 106.It e 107Print the assertion message to the 108.Dv stderr 109stream. 110.It E 111Opposite of 112.Dq e . 113.It l 114Log the assertion message with 115.Xr syslog 3 116to the facility 117.Dv user.debug . 118.It L 119Opposite of 120.Dq l . 121.El 122.Sh DIAGNOSTICS 123The diagnostic message has the following format: 124.Bd -literal -offset indent 125"assertion \e"%s\e" failed: file \e"%s\e", line %d, function \e"%s\e"\en", 126 "expression", __FILE__, __LINE__, __func__ 127.Ed 128.Sh SEE ALSO 129.Xr cc 1 , 130.Xr abort 3 , 131.Xr assert 3 132.Sh HISTORY 133The 134.Nm _DIAGASSERT 135macro appeared in 136.Nx 1.5 . 137