131 lines
3.6 KiB
Groff
131 lines
3.6 KiB
Groff
.\" $NetBSD: _DIAGASSERT.3,v 1.8 2008/04/30 13:10:53 martin Exp $
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.\"
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.\" Copyright (c) 2001 The NetBSD Foundation, Inc.
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.\" All rights reserved.
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.\"
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.\" This code is derived from software contributed to The NetBSD Foundation
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.\" by Luke Mewburn.
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.\"
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.\" Redistribution and use in source and binary forms, with or without
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.\" modification, are permitted provided that the following conditions
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.\" are met:
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.\" 1. Redistributions of source code must retain the above copyright
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.\" notice, this list of conditions and the following disclaimer.
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.\" 2. Redistributions in binary form must reproduce the above copyright
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.\" notice, this list of conditions and the following disclaimer in the
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.\" documentation and/or other materials provided with the distribution.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS
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.\" ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED
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.\" TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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.\" PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS
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.\" BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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.\" CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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.\" SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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.\" INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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.\" CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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.\" POSSIBILITY OF SUCH DAMAGE.
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.\"
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.Dd January 22, 2007
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.Dt _DIAGASSERT 3
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.Os
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.Sh NAME
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.Nm _DIAGASSERT
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.Nd expression verification macro
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.Sh SYNOPSIS
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.In assert.h
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.Fn _DIAGASSERT expression
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.Sh DESCRIPTION
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The
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.Fn _DIAGASSERT
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macro tests the given
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.Ar expression
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and if it is false, one or more of the following may occur:
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.Bl -bullet -offset indent
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.It
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a diagnostic message may be logged to the system logger with
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.Xr syslog 3 .
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This is default behaviour.
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.It
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a diagnostic message may be printed to the
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.Dv stderr
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stream.
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.It
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the calling process will be terminated by calling
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.Xr abort 3 .
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.El
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.Pp
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This behaviour may be changed by setting the
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.Ev LIBC_DIAGASSERT
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environment variable (see below).
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.Pp
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The diagnostic message consists of the text of the expression,
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the name of the source file, the line number and the enclosing
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function.
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.Pp
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If
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.Ar expression
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is true,
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the
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.Fn _DIAGASSERT
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macro does nothing.
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.Pp
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The
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.Fn _DIAGASSERT
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macro is not compiled in by default, and will only be compiled in with the
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.Xr cc 1
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option
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.Fl D_DIAGNOSTIC .
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.Pp
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This macro is used in the various system libraries such as the
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.Lb libc
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to ensure that various library calls are invoked with valid arguments.
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.Sh ENVIRONMENT
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The
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.Ev LIBC_DIAGASSERT
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environment variable can be used to modify the default behaviour of
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logging the assertion to the system logger.
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.Pp
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.Ev LIBC_DIAGASSERT
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may be set to one or more of the following characters:
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.Bl -tag -width xxx -offset indent
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.It a
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.Xr abort 3
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once any assertion messages have been logged and/or printed.
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.It A
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Opposite of
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.Dq a .
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.It e
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Print the assertion message to the
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.Dv stderr
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stream.
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.It E
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Opposite of
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.Dq e .
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.It l
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Log the assertion message with
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.Xr syslog 3
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to the facility
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.Dv user.debug .
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.It L
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Opposite of
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.Dq l .
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.El
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.Sh DIAGNOSTICS
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The diagnostic message has the following format:
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.Bd -literal -offset indent
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"assertion \e"%s\e" failed: file \e"%s\e", line %d, function \e"%s\e"\en",
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"expression", __FILE__, __LINE__, __func__
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.Ed
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.Sh SEE ALSO
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.Xr cc 1 ,
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.Xr abort 3 ,
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.Xr assert 3 ,
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.Xr syslog 3
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.Sh HISTORY
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The
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.Nm _DIAGASSERT
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macro appeared in
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.Nx 1.5 .
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