getenv — get an environment variable
#include <stdlib.h>
char
*getenv( |
const char *name); |
The getenv() function
searches the environment list to find the environment
variable name, and
returns a pointer to the corresponding value string.
The getenv() function
returns a pointer to the value in the environment, or NULL if
there is no match.
The strings in the environment list are of the form
name=value.
As typically implemented, getenv() returns a pointer to a string
within the environment list. The caller must take care not to
modify this string, since that would change the environment
of the process.
The implementation of getenv() is not required to be reentrant.
The string pointed to by the return value of getenv() may be statically allocated, and
can be modified by a subsequent call to getenv(), putenv(3), setenv(3), or unsetenv(3).
This page is part of release 3.33 of the Linux man-pages project. A
description of the project, and information about reporting
bugs, can be found at http://man7.org/linux/man-pages/.
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Copyright 1993 David Metcalfe (davidprism.demon.co.uk) and Copyright (C) 2007 Michael Kerrisk <mtk.manpagesgmail.com> 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 Since the Linux kernel and libraries are constantly changing, this manual page may be incorrect or out-of-date.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 (faithcs.unc.edu) Modified Fri Feb 14 21:47:50 1997 by Andries Brouwer (aebcwi.nl) |