.\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk) .\" and Copyright (C) 2007 Michael Kerrisk .\" .\" Permission is granted to make and distribute verbatim copies of this .\" manual provided the copyright notice and this permission notice are .\" preserved on all copies. .\" .\" Permission is granted to copy and distribute modified versions of this .\" manual under the conditions for verbatim copying, provided that the .\" entire resulting derived work is distributed under the terms of a .\" permission notice identical to this one. .\" .\" Since the Linux kernel and libraries are constantly changing, this .\" manual page may be incorrect or out-of-date. The author(s) assume no .\" responsibility for errors or omissions, or for damages resulting from .\" the use of the information contained herein. The author(s) may not .\" have taken the same level of care in the production of this manual, .\" which is licensed free of charge, as they might when working .\" professionally. .\" .\" Formatted or processed versions of this manual, if unaccompanied by .\" the source, must acknowledge the copyright and authors of this work. .\" .\" References consulted: .\" Linux libc source code .\" Lewine's "POSIX Programmer's Guide" (O'Reilly & Associates, 1991) .\" 386BSD man pages .\" Modified Sat Jul 24 19:30:29 1993 by Rik Faith (faith@cs.unc.edu) .\" Modified Fri Feb 14 21:47:50 1997 by Andries Brouwer (aeb@cwi.nl) .\" .\" Japanese Version Copyright (c) 1997 Taro Morioka .\" all rights reserved. .\" Translated Tue 08 04 06:00:00 JST 1997 .\" by Tarho Morioka (t-morioka@nri.co.jp) .\" Modified 2003-09-27 by NAKANO Takeo .\" Updated 2008-08-07, Akihiro MOTOKI , LDP v3.05 .\" .TH GETENV 3 2008-03-17 "GNU" "Linux Programmer's Manual" .\"O .SH NAME .\"O getenv \- get an environment variable .SH 名前 getenv \- 環境変数を得る .\"O .SH SYNOPSIS .SH 書式 .nf .B #include .sp .BI "char *getenv(const char *" name ); .fi .\"O .SH DESCRIPTION .SH 説明 .\"O The .\"O .BR getenv () .\"O function searches the environment list to find the .\"O environment variable .\"O .IR name , .\"O and returns a pointer to the corresponding .\"O .I value .\"O string. 関数 .BR getenv () は、環境リストから名前が .I name の環境変数を検索し、対応する .I value 文字列へのポインタを返す。 .\"O .SH "RETURN VALUE" .SH 返り値 .\"O The .\"O .BR getenv () .\"O function returns a pointer to the value in the .\"O environment, or NULL if there is no match. 関数 .BR getenv () は、環境における値 value へのポインタを返す。 \fIname\fP にマッチする環境変数が存在しないときには NULL を返す。 .\"O .SH "CONFORMING TO" .SH 準拠 SVr4, POSIX.1-2001, 4.3BSD, C89, C99. .\"O .SH NOTES .SH 注意 .\"O The strings in the environment list are of the form \fIname=value\fP. 環境リストの文字列は \fIname=value\fP という形式をしている。 .\"O As typically implemented, .\"O .BR getenv () .\"O returns a pointer to a string within the environment list. .\"O The caller must take care not to modify this string, .\"O since that would change the environment of the process. 通常の実装では、 .BR getenv () は環境リスト内の文字列へのポインタを返す。 呼び出し元はこの文字列を変更しないように注意しなければならない。 この文字列を変更すると、そのプロセスの環境を変化させることになるからである。 .\"O The implementation of .\"O .BR getenv () .\"O is not required to be reentrant. .\"O The string pointed to by the return value of .\"O .BR getenv () .\"O may be statically allocated, .\"O and can be modified by a subsequent call to .\"O .BR getenv (), .\"O .BR putenv (3), .\"O .BR setenv (3), .\"O or .\"O .BR unsetenv (3). .BR getenv () の実装はリエントラント (再入可能) であることを要求されていない。 .BR getenv () の返り値により参照される文字列は静的に割り当てられてもよく、 文字列の内容は後続の .BR getenv (), .BR putenv (3), .BR setenv (3), .BR unsetenv (3) の呼び出しにより変更されることがある。 .\"O .SH "SEE ALSO" .SH 関連項目 .BR clearenv (3), .BR putenv (3), .BR setenv (3), .BR unsetenv (3), .BR environ (7)