.\"	$OpenBSD: err.3,v 1.2 1996/08/19 08:22:28 tholo Exp $
.\"
.\" Copyright (c) 1993
.\"	The Regents of the University of California.  All rights reserved.
.\"
.\" Redistribution and use in source and binary forms, with or without
.\" modification, are permitted provided that the following conditions
.\" are met:
.\" 1. Redistributions of source code must retain the above copyright
.\"    notice, this list of conditions and the following disclaimer.
.\" 2. Redistributions in binary form must reproduce the above copyright
.\"    notice, this list of conditions and the following disclaimer in the
.\"    documentation and/or other materials provided with the distribution.
.\" 3. All advertising materials mentioning features or use of this software
.\"    must display the following acknowledgement:
.\"	This product includes software developed by the University of
.\"	California, Berkeley and its contributors.
.\" 4. Neither the name of the University nor the names of its contributors
.\"    may be used to endorse or promote products derived from this software
.\"    without specific prior written permission.
.\"
.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
.\" ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
.\" SUCH DAMAGE.
.\"
.\" Japanese Version Copyright (c) 2000 Yuichi SATO
.\"         all rights reserved.
.\" Translated Thu Dec 14 18:22:51 JST 2000
.\"         by Yuichi SATO <sato@complex.eng.hokudai.ac.jp>
.\"
.Dd June 9, 1993
.Dt ERR 3
.Os "Linux NetKit (0.17)"
.Sh 名前
.Nm err ,
.Nm verr ,
.Nm errx ,
.Nm verrx ,
.Nm warn ,
.Nm vwarn ,
.Nm warnx ,
.Nm vwarnx
.Nd エラーメッセージをフォーマットにする
.Sh 書式
.Fd #include <err.h>
.Ft void
.Fn err "int eval" "const char *fmt" "..."
.Ft void
.Fn verr "int eval" "const char *fmt" "va_list args"
.Ft void
.Fn errx "int eval" "const char *fmt" "..."
.Ft void
.Fn verrx "int eval" "const char *fmt" "va_list args"
.Ft void
.Fn warn "const char *fmt" "..."
.Ft void
.Fn vwarn "const char *fmt" "va_list args"
.Ft void
.Fn warnx "const char *fmt" "..."
.Ft void
.Fn vwarnx "const char *fmt" "va_list args"
.Sh 説明
.Fn err
や
.Fn warn
といった一連の関数は、フォーマットされたエラーメッセージを
標準エラーに表示する。
これら全ての関数は、プログラム名からディレクトリ部分を取り去った名前に、
コロンとスペースを続けたものを出力する。
引き数
.Va fmt
が NULL でない場合、フォーマットされたエラーメッセージ・
コロン・スペースが出力される。
.Fn err ,
.Fn verr ,
.Fn warn ,
.Fn vwarn
関数の場合、大域変数
.Va errno
の現在の値に対応したエラーメッセージ文字列が出力される。
全ての関数で、出力の後には改行文字が付く。
.Pp
.Fn err ,
.Fn verr ,
.Fn errx ,
.Fn verrx
関数はリターンせず、引き数
.Fa eval
の値で終了する。
.Sh 例
現在のエラー番号 (errno) 情報の文字列を表示して終了する:
.Bd -literal -offset indent
if ((p = malloc(size)) == NULL)
	err(1, NULL);
if ((fd = open(file_name, O_RDONLY, 0)) == -1)
	err(1, "%s", file_name);
.Ed
.Pp
エラーメッセージを表示して終了する:
.Bd -literal -offset indent
if (tm.tm_hour < START_TIME)
	errx(1, "too early, wait until %s", start_time_string);
.Ed
.Pp
エラーの警告を出す:
.Bd -literal -offset indent
if ((fd = open(raw_device, O_RDONLY, 0)) == -1)
	warnx("%s: %s: trying the block device",
	    raw_device, strerror(errno));
if ((fd = open(block_device, O_RDONLY, 0)) == -1)
	err(1, "%s", block_device);
.Ed
.Sh 関連項目
.Xr strerror 3
.Sh 履歴
.Fn err
と
.Fn warn
関数は
.Bx 4.4
で初めて登場した。