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.\" Copyright (C) 2006 Michael Kerrisk <mtk.manpages@gmail.com>
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.\" Japanese Version Copyright (c) 2006 Akihiro MOTOKI all rights reserved.
.\" Translated 2006-04-18, Akihiro MOTOKI <amotoki@dd.iij4u.or.jp>
.\"
.TH SEM_POST 3 2009-03-30 "Linux" "Linux Programmer's Manual"
.\"O .SH NAME
.SH 名前
.\"O sem_post \- unlock a semaphore
sem_post \- セマフォのロックを解除する
.\"O .SH SYNOPSIS
.SH 書式
.nf
.B #include <semaphore.h>
.sp
.BI "int sem_post(sem_t *" sem );
.fi
.sp
.\"O Link with \fI\-lrt\fP or \fI\-pthread\fP.
\fI\-lrt\fP または \fI\-pthread\fP でリンクする。
.\"O .SH DESCRIPTION
.SH 説明
.\"O .BR sem_post ()
.\"O increments (unlocks) the semaphore pointed to by
.\"O .IR sem .
.\"O If the semaphore's value consequently becomes greater than zero,
.\"O then another process or thread blocked in a
.\"O .BR sem_wait (3)
.\"O call will be woken up and proceed to lock the semaphore.
.BR sem_post ()
は、
.I sem
が指すセマフォの値を 1 増やす (ロックを解除する)。その結果、
セマフォの値は 0 より大きな値に変化し、
.BR sem_wait (3)
で停止している別のプロセスやスレッドが呼び起こされ、
セマフォをロックできるようになる。
.\"O .SH RETURN VALUE
.SH 返り値
.\"O .BR sem_post ()
.\"O returns 0 on success;
.\"O on error, the value of the semaphore is left unchanged,
.\"O \-1 is returned, and
.\"O .I errno
.\"O is set to indicate the error.
成功すると、
.BR sem_post ()
は 0 を返す。エラーの場合、セマフォの値は変更せずに、 \-1 を返し、
.I errno
にエラーを示す値をセットする。
.\"O .SH ERRORS
.SH エラー
.TP
.B EINVAL
.\"O .I sem
.\"O is not a valid semaphore.
.I sem
は有効なセマフォではない。
.TP
.B EOVERFLOW
.\" Added in POSIX.1-2008 TC1 (Austin Interpretation 213)
.\"O The maximum allowable value for a semaphore would be exceeded.
一つのセマフォで使用できる最大値を超えてしまうところであった。
.\"O .SH CONFORMING TO
.SH 準拠
POSIX.1-2001.
.\"O .SH NOTES
.SH 注意
.\"O .BR sem_post ()
.\"O is async-signal-safe:
.\"O it may be safely called within a signal handler.
.BR sem_post ()
は async-signal-safe である。
つまり、シグナルハンドラの中でも安全に呼び出すことができる。
.\"O .SH EXAMPLE
.SH 例
.\"O See
.\"O .BR sem_wait (3).
.BR sem_wait (3)
参照。
.\"O .SH "SEE ALSO"
.SH 関連項目
.BR sem_getvalue (3),
.BR sem_wait (3),
.BR sem_overview (7)