1.\" Copyright (c) 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.\" From: @(#)err.3 8.1 (Berkeley) 6/9/93 33.\" $Id: err.3,v 1.8 1998/04/22 19:59:55 rnordier Exp $ 34.\" 35.Dd April 13, 1995 36.Dt ERR 3 37.Os BSD 4 38.Sh NAME 39.Nm err , 40.Nm verr , 41.Nm errc , 42.Nm verrc , 43.Nm errx , 44.Nm verrx , 45.Nm warn , 46.Nm vwarn , 47.Nm warnc , 48.Nm vwarnc , 49.Nm warnx , 50.Nm vwarnx , 51.Nm err_set_file , 52.Nm err_set_exit 53.Nd formatted error messages 54.Sh SYNOPSIS 55.Fd #include <err.h> 56.Ft void 57.Fn err "int eval" "const char *fmt" "..." 58.Ft void 59.Fn errc "int eval" "int code" "const char *fmt" "..." 60.Ft void 61.Fn errx "int eval" "const char *fmt" "..." 62.Ft void 63.Fn warn "const char *fmt" "..." 64.Ft void 65.Fn warnc "int code" "const char *fmt" "..." 66.Ft void 67.Fn warnx "const char *fmt" "..." 68.Fd #include <stdio.h> 69.Ft void 70.Fn err_set_file "FILE *fp" 71.Ft void 72.Fn err_set_exit "void (*exitf)(int)" 73.Fd #include <stdarg.h> 74.Ft void 75.Fn verr "int eval" "const char *fmt" "va_list args" 76.Ft void 77.Fn verrc "int eval" "int code" "const char *fmt" "va_list args" 78.Ft void 79.Fn verrx "int eval" "const char *fmt" "va_list args" 80.Ft void 81.Fn vwarn "const char *fmt" "va_list args" 82.Ft void 83.Fn vwarnc "int code" "const char *fmt" "va_list args" 84.Ft void 85.Fn vwarnx "const char *fmt" "va_list args" 86.Sh DESCRIPTION 87The 88.Fn err 89and 90.Fn warn 91family of functions display a formatted error message on the standard 92error output, or on another file specified using the 93.Fn err_set_file 94function. 95In all cases, the last component of the program name, a colon character, 96and a space are output. 97If the 98.Va fmt 99argument is not NULL, the formatted error message is output. 100In the case of the 101.Fn errc , 102.Fn verrc , 103.Fn warnc , 104and 105.Fn vwarnc 106functions, 107the error message string affiliated with the 108.Va code 109argument is also output, 110preceded by another colon and space if necessary. 111In all cases, the output is followed by a newline character. 112.Pp 113The 114.Fn err , 115.Fn verr , 116.Fn warn , 117and 118.Fn vwarn 119functions use the global variable 120.Va errno 121rather than the 122.Va code 123argument of the 124.Fn errc 125family 126.Pp 127The 128.Fn err , 129.Fn verr , 130.Fn errc , 131.Fn verrc , 132.Fn errx , 133and 134.Fn verrx 135functions do not return, but exit with the value of the argument 136.Fa eval . 137The 138.Fn err_set_exit 139function can be used to specify a function which is called before 140.Xr exit 3 141to perform any necessary cleanup; passing a null function pointer for 142.Va exitf 143resets the hook to do nothing. 144.Sh EXAMPLES 145Display the current errno information string and exit: 146.Bd -literal -offset indent 147if ((p = malloc(size)) == NULL) 148 err(1, NULL); 149if ((fd = open(file_name, O_RDONLY, 0)) == -1) 150 err(1, "%s", file_name); 151.Ed 152.Pp 153Display an error message and exit: 154.Bd -literal -offset indent 155if (tm.tm_hour < START_TIME) 156 errx(1, "too early, wait until %s", start_time_string); 157.Ed 158.Pp 159Warn of an error: 160.Bd -literal -offset indent 161if ((fd = open(raw_device, O_RDONLY, 0)) == -1) 162 warnx("%s: %s: trying the block device", 163 raw_device, strerror(errno)); 164if ((fd = open(block_device, O_RDONLY, 0)) == -1) 165 err(1, "%s", block_device); 166.Ed 167.Pp 168Warn of an error without using the global variable 169.Va errno : 170.Bd -literal -offset indent 171error = my_function(); /* returns a value from <errno.h> */ 172if (error != 0) 173 warnc(error, "my_function"); 174.Ed 175.Sh SEE ALSO 176.Xr exit 3 , 177.Xr strerror 3 178.Sh HISTORY 179The 180.Fn err 181and 182.Fn warn 183functions first appeared in 184.Bx 4.4 . 185The 186.Fn err_set_file 187and 188.Fn err_set_exit 189functions first appeared in 190.Fx 2.1 . 191The 192.Fn errc 193and 194.Fn warnc 195functions first appeared in 196.Fx 3.0 . 197