mirror of https://github.com/mkerrisk/man-pages
162 lines
4.4 KiB
Groff
162 lines
4.4 KiB
Groff
.\" Copyright (c) 1993
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.\" The Regents of the University of California. All rights reserved.
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.\"
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.\" %%%LICENSE_START(BSD_4_CLAUSE_UCB)
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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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.\" 3. All advertising materials mentioning features or use of this software
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.\" must display the following acknowledgement:
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.\" This product includes software developed by the University of
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.\" California, Berkeley and its contributors.
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.\" 4. Neither the name of the University nor the names of its contributors
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.\" may be used to endorse or promote products derived from this software
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.\" without specific prior written permission.
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.\"
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.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
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.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
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.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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.\" SUCH DAMAGE.
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.\" %%%LICENSE_END
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.\"
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.\" From: @(#)err.3 8.1 (Berkeley) 6/9/93
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.\" $FreeBSD: src/lib/libc/gen/err.3,v 1.11.2.5 2001/08/17 15:42:32 ru Exp $
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.\"
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.\" 2011-09-10, mtk, Converted from mdoc to man macros
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.\"
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.TH ERR 3 2013-12-30 "Linux" "Linux Programmer's Manual"
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.SH NAME
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err, verr, errx, verrx, warn, vwarn, warnx, vwarnx \- formatted error messages
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.SH SYNOPSIS
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.nf
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.B #include <err.h>
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.sp
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.BI "void err(int " eval ", const char *" fmt ", ...);"
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.sp
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.BI "void errx(int " eval ", const char *" fmt ", ...);"
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.sp
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.BI "void warn(const char *" fmt ", ...);"
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.sp
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.BI "void warnx(const char *" fmt ", ...);"
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.sp
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.B #include <stdarg.h>
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.sp
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.BI "void verr(int " eval ", const char *" fmt ", va_list " args );
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.sp
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.BI "void verrx(int " eval ", const char *" fmt ", va_list " args );
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.sp
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.BI "void vwarn(const char *" fmt ", va_list " args );
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.sp
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.BI "void vwarnx(const char *" fmt ", va_list " args );
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.fi
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.SH DESCRIPTION
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The
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.BR err ()
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and
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.BR warn ()
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family of functions display a formatted error message on the standard
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error output.
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In all cases, the last component of the program name, a colon character,
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and a space are output.
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If the
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.I fmt
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argument is not NULL, the
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.BR printf (3)-like
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formatted error message is output.
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The output is terminated by a newline character.
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.PP
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The
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.BR err (),
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.BR verr (),
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.BR warn (),
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and
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.BR vwarn ()
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functions append an error message obtained from
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.BR strerror (3)
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based on the global variable
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.IR errno ,
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preceded by another colon and space unless the
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.I fmt
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argument is
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NULL.
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.PP
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The
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.BR errx ()
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and
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.BR warnx ()
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functions do not append an error message.
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.PP
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The
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.BR err (),
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.BR verr (),
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.BR errx (),
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and
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.BR verrx ()
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functions do not return, but exit with the value of the argument
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.IR eval .
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.SH CONFORMING TO
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These functions are nonstandard BSD extensions.
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.\" .SH HISTORY
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.\" The
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.\" .BR err ()
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.\" and
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.\" .BR warn ()
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.\" functions first appeared in
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.\" 4.4BSD.
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.SH EXAMPLE
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Display the current
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.I errno
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information string and exit:
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.in +4n
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.nf
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p = malloc(size);
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if (p == NULL)
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err(1, NULL);
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fd = open(file_name, O_RDONLY, 0);
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if (fd == \-1)
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err(1, "%s", file_name);
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.fi
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.in
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.PP
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Display an error message and exit:
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.in +4n
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.nf
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if (tm.tm_hour < START_TIME)
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errx(1, "too early, wait until %s", start_time_string);
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.fi
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.in
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.PP
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Warn of an error:
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.in +4n
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.nf
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fd = open(raw_device, O_RDONLY, 0);
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if (fd == \-1)
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warnx("%s: %s: trying the block device",
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raw_device, strerror(errno));
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fd = open(block_device, O_RDONLY, 0);
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if (fd == \-1)
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err(1, "%s", block_device);
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.fi
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.in
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.SH SEE ALSO
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.BR error (3),
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.BR exit (3),
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.BR perror (3),
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.BR printf (3),
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.BR strerror (3)
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