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.\" $FreeBSD$ 34.\" 35.Dd Mar 6, 1999 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_exit , 52.Nm err_set_file 53.Nd formatted error messages 54.Sh LIBRARY 55.Lb libc 56.Sh SYNOPSIS 57.Fd #include <err.h> 58.Ft void 59.Fn err "int eval" "const char *fmt" "..." 60.Ft void 61.Fn err_set_exit "void (*exitf)(int)" 62.Ft void 63.Fn err_set_file "void *vfp" 64.Ft void 65.Fn errc "int eval" "int code" "const char *fmt" "..." 66.Ft void 67.Fn errx "int eval" "const char *fmt" "..." 68.Ft void 69.Fn warn "const char *fmt" "..." 70.Ft void 71.Fn warnc "int code" "const char *fmt" "..." 72.Ft void 73.Fn warnx "const char *fmt" "..." 74.Fd #include <stdarg.h> 75.Ft void 76.Fn verr "int eval" "const char *fmt" "va_list args" 77.Ft void 78.Fn verrc "int eval" "int code" "const char *fmt" "va_list args" 79.Ft void 80.Fn verrx "int eval" "const char *fmt" "va_list args" 81.Ft void 82.Fn vwarn "const char *fmt" "va_list args" 83.Ft void 84.Fn vwarnc "int code" "const char *fmt" "va_list args" 85.Ft void 86.Fn vwarnx "const char *fmt" "va_list args" 87.Sh DESCRIPTION 88The 89.Fn err 90and 91.Fn warn 92family of functions display a formatted error message on the standard 93error output, or on another file specified using the 94.Fn err_set_file 95function. 96In all cases, the last component of the program name, a colon character, 97and a space are output. 98If the 99.Fa fmt 100argument is not NULL, the formatted error message is output. 101The output is terminated by a newline character. 102.Pp 103The 104.Fn err , 105.Fn errc , 106.Fn verr , 107.Fn verrc , 108.Fn warn , 109.Fn warnc , 110.Fn vwarn , 111and 112.Fn vwarnc 113functions append an error message obtained from 114.Xr strerror 3 115based on a code or the global variable 116.Va errno , 117preceeded by another colon and space unless the 118.Fa fmt 119argument is 120.Dv NULL . 121.Pp 122In the case of the 123.Fn errc , 124.Fn verrc , 125.Fn warnc , 126and 127.Fn vwarnc 128functions, 129the 130.Fa code 131argument is used to look up the error message. 132.Pp 133The 134.Fn err , 135.Fn verr , 136.Fn warn , 137and 138.Fn vwarn 139functions use the global variable 140.Va errno 141to look up the error message. 142.Pp 143The 144.Fn errx 145and 146.Fn warnx 147functions do not append an error message. 148.Pp 149The 150.Fn err , 151.Fn verr , 152.Fn errc , 153.Fn verrc , 154.Fn errx , 155and 156.Fn verrx 157functions do not return, but exit with the value of the argument 158.Fa eval . 159The 160.Fn err_set_exit 161function can be used to specify a function which is called before 162.Xr exit 3 163to perform any necessary cleanup; passing a null function pointer for 164.Va exitf 165resets the hook to do nothing. 166The 167.Fn err_set_file 168function sets the output stream used by the other functions. 169Its 170.Fa vfp 171argument must be either a pointer to an open stream 172(possibly already converted to void *) 173or a null pointer 174(in which case the output stream is set to standard error). 175.Sh EXAMPLES 176Display the current errno information string and exit: 177.Bd -literal -offset indent 178if ((p = malloc(size)) == NULL) 179 err(1, NULL); 180if ((fd = open(file_name, O_RDONLY, 0)) == -1) 181 err(1, "%s", file_name); 182.Ed 183.Pp 184Display an error message and exit: 185.Bd -literal -offset indent 186if (tm.tm_hour < START_TIME) 187 errx(1, "too early, wait until %s", start_time_string); 188.Ed 189.Pp 190Warn of an error: 191.Bd -literal -offset indent 192if ((fd = open(raw_device, O_RDONLY, 0)) == -1) 193 warnx("%s: %s: trying the block device", 194 raw_device, strerror(errno)); 195if ((fd = open(block_device, O_RDONLY, 0)) == -1) 196 err(1, "%s", block_device); 197.Ed 198.Pp 199Warn of an error without using the global variable 200.Va errno : 201.Bd -literal -offset indent 202error = my_function(); /* returns a value from <errno.h> */ 203if (error != 0) 204 warnc(error, "my_function"); 205.Ed 206.Sh SEE ALSO 207.Xr exit 3 , 208.Xr strerror 3 209.Sh HISTORY 210The 211.Fn err 212and 213.Fn warn 214functions first appeared in 215.Bx 4.4 . 216The 217.Fn err_set_exit 218and 219.Fn err_set_file 220functions first appeared in 221.Fx 2.1 . 222The 223.Fn errc 224and 225.Fn warnc 226functions first appeared in 227.Fx 3.0 . 228