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.\" @(#)err.3 8.1 (Berkeley) 6/9/93 33.\" 34.Dd "June 9, 1993" 35.Dt ERR 3 36.Os BSD 4 37.Sh NAME 38.Nm err , 39.Nm verr , 40.Nm errx , 41.Nm verrx , 42.Nm warn , 43.Nm vwarn , 44.Nm warnx , 45.Nm vwarnx 46.Nd formatted error messages 47.Sh SYNOPSIS 48.Fd #include <err.h> 49.Ft void 50.Fn err "int eval" "const char *fmt" "..." 51.Ft void 52.Fn verr "int eval" "const char *fmt" "va_list args" 53.Ft void 54.Fn errx "int eval" "const char *fmt" "..." 55.Ft void 56.Fn verrx "int eval" "const char *fmt" "va_list args" 57.Ft void 58.Fn warn "const char *fmt" "..." 59.Ft void 60.Fn vwarn "const char *fmt" "va_list args" 61.Ft void 62.Fn warnx "const char *fmt" "..." 63.Ft void 64.Fn vwarnx "const char *fmt" "va_list args" 65.Sh DESCRIPTION 66The 67.Fn err 68and 69.Fn warn 70family of functions display a formatted error message on the standard 71error output. 72In all cases, the last component of the program name, a colon character, 73and a space are output. 74If the 75.Va fmt 76argument is not NULL, the formatted error message, a colon character, 77and a space are output. 78In the case of the 79.Fn err , 80.Fn verr , 81.Fn warn , 82and 83.Fn vwarn 84functions, the error message string affiliated with the current value of 85the global variable 86.Va errno 87is output. 88In all cases, the output is followed by a newline character. 89.Pp 90The 91.Fn err , 92.Fn verr , 93.Fn errx , 94and 95.Fn verrx 96functions do not return, but exit with the value of the argument 97.Fa eval . 98.Sh EXAMPLES 99Display the current errno information string and exit: 100.Bd -literal -offset indent 101if ((p = malloc(size)) == NULL) 102 err(1, NULL); 103if ((fd = open(file_name, O_RDONLY, 0)) == -1) 104 err(1, "%s", file_name); 105.Ed 106.Pp 107Display an error message and exit: 108.Bd -literal -offset indent 109if (tm.tm_hour < START_TIME) 110 errx(1, "too early, wait until %s", start_time_string); 111.Ed 112.Pp 113Warn of an error: 114.Bd -literal -offset indent 115if ((fd = open(raw_device, O_RDONLY, 0)) == -1) 116 warnx("%s: %s: trying the block device", 117 raw_device, strerror(errno)); 118if ((fd = open(block_device, O_RDONLY, 0)) == -1) 119 err(1, "%s", block_device); 120.Ed 121.Sh SEE ALSO 122.Xr strerror 3 123.Sh HISTORY 124The 125.Fn err 126and 127.Fn warn 128functions first appeared in 4.4BSD. 129