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.Va fmt 100argument is not NULL, the formatted error message is output. 101In the case of the 102.Fn errc , 103.Fn verrc , 104.Fn warnc , 105and 106.Fn vwarnc 107functions, 108the error message string affiliated with the 109.Va code 110argument is also output, 111preceded by another colon and space if necessary. 112In all cases, the output is followed by a newline character. 113.Pp 114The 115.Fn err , 116.Fn verr , 117.Fn warn , 118and 119.Fn vwarn 120functions use the global variable 121.Va errno 122rather than the 123.Va code 124argument of the 125.Fn errc 126family 127.Pp 128The 129.Fn err , 130.Fn verr , 131.Fn errc , 132.Fn verrc , 133.Fn errx , 134and 135.Fn verrx 136functions do not return, but exit with the value of the argument 137.Fa eval . 138The 139.Fn err_set_exit 140function can be used to specify a function which is called before 141.Xr exit 3 142to perform any necessary cleanup; passing a null function pointer for 143.Va exitf 144resets the hook to do nothing. 145The 146.Fn err_set_file 147function sets the output stream used by the other functions. 148Its 149.Va vfp 150argument must be either a pointer to an open stream 151(possibly already converted to void *) 152or a null pointer 153(in which case the output stream is set to standard error). 154.Sh EXAMPLES 155Display the current errno information string and exit: 156.Bd -literal -offset indent 157if ((p = malloc(size)) == NULL) 158 err(1, NULL); 159if ((fd = open(file_name, O_RDONLY, 0)) == -1) 160 err(1, "%s", file_name); 161.Ed 162.Pp 163Display an error message and exit: 164.Bd -literal -offset indent 165if (tm.tm_hour < START_TIME) 166 errx(1, "too early, wait until %s", start_time_string); 167.Ed 168.Pp 169Warn of an error: 170.Bd -literal -offset indent 171if ((fd = open(raw_device, O_RDONLY, 0)) == -1) 172 warnx("%s: %s: trying the block device", 173 raw_device, strerror(errno)); 174if ((fd = open(block_device, O_RDONLY, 0)) == -1) 175 err(1, "%s", block_device); 176.Ed 177.Pp 178Warn of an error without using the global variable 179.Va errno : 180.Bd -literal -offset indent 181error = my_function(); /* returns a value from <errno.h> */ 182if (error != 0) 183 warnc(error, "my_function"); 184.Ed 185.Sh SEE ALSO 186.Xr exit 3 , 187.Xr strerror 3 188.Sh HISTORY 189The 190.Fn err 191and 192.Fn warn 193functions first appeared in 194.Bx 4.4 . 195The 196.Fn err_set_exit 197and 198.Fn err_set_file 199functions first appeared in 200.Fx 2.1 . 201The 202.Fn errc 203and 204.Fn warnc 205functions first appeared in 206.Fx 3.0 . 207