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 1.6 1997/02/22 14:58:02 peter 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 errx , 42.Nm verrx , 43.Nm warn , 44.Nm vwarn , 45.Nm warnx , 46.Nm vwarnx , 47.Nm err_set_file , 48.Nm err_set_exit 49.Nd formatted error messages 50.Sh SYNOPSIS 51.Fd #include <err.h> 52.Ft void 53.Fn err "int eval" "const char *fmt" "..." 54.Ft void 55.Fn errx "int eval" "const char *fmt" "..." 56.Ft void 57.Fn warn "const char *fmt" "..." 58.Ft void 59.Fn warnx "const char *fmt" "..." 60.Ft void 61.Fn err_set_file "void *fp" 62.Ft void 63.Fn err_set_exit "void (*exitf)(int)" 64.Fd #include <stdarg.h> 65.Ft void 66.Fn verr "int eval" "const char *fmt" "va_list args" 67.Ft void 68.Fn verrx "int eval" "const char *fmt" "va_list args" 69.Ft void 70.Fn vwarn "const char *fmt" "va_list args" 71.Ft void 72.Fn vwarnx "const char *fmt" "va_list args" 73.Sh DESCRIPTION 74The 75.Fn err 76and 77.Fn warn 78family of functions display a formatted error message on the standard 79error output, or on another file specified using the 80.Fn err_set_file 81function. 82In all cases, the last component of the program name, a colon character, 83and a space are output. 84If the 85.Va fmt 86argument is not NULL, the formatted error message, a colon character, 87and a space are output. 88In the case of the 89.Fn err , 90.Fn verr , 91.Fn warn , 92and 93.Fn vwarn 94functions, the error message string affiliated with the current value of 95the global variable 96.Va errno 97is output. 98In all cases, the output is followed by a newline character. 99.Pp 100The 101.Fn err , 102.Fn verr , 103.Fn errx , 104and 105.Fn verrx 106functions do not return, but exit with the value of the argument 107.Fa eval . 108The 109.Fn err_set_exit 110function can be used to specify a function which is called before 111.Xr exit 3 112to perform any necessary cleanup; passing a null function pointer for 113.Va exitf 114resets the hook to do nothing. 115.Sh EXAMPLES 116Display the current errno information string and exit: 117.Bd -literal -offset indent 118if ((p = malloc(size)) == NULL) 119 err(1, NULL); 120if ((fd = open(file_name, O_RDONLY, 0)) == -1) 121 err(1, "%s", file_name); 122.Ed 123.Pp 124Display an error message and exit: 125.Bd -literal -offset indent 126if (tm.tm_hour < START_TIME) 127 errx(1, "too early, wait until %s", start_time_string); 128.Ed 129.Pp 130Warn of an error: 131.Bd -literal -offset indent 132if ((fd = open(raw_device, O_RDONLY, 0)) == -1) 133 warnx("%s: %s: trying the block device", 134 raw_device, strerror(errno)); 135if ((fd = open(block_device, O_RDONLY, 0)) == -1) 136 err(1, "%s", block_device); 137.Ed 138.Sh SEE ALSO 139.Xr exit 3 , 140.Xr strerror 3 141.Sh HISTORY 142The 143.Fn err 144and 145.Fn warn 146functions first appeared in 147.Bx 4.4 . 148