Name

getenv — get an environment variable

Synopsis

#include <stdlib.h>
char *getenv( const char *name);
 

DESCRIPTION

The getenv() function searches the environment list to find the environment variable name, and returns a pointer to the corresponding value string.

RETURN VALUE

The getenv() function returns a pointer to the value in the environment, or NULL if there is no match.

CONFORMING TO

SVr4, POSIX.1-2001, 4.3BSD, C89, C99.

NOTES

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).

SEE ALSO

clearenv(3), putenv(3), setenv(3), unsetenv(3), environ(7)

COLOPHON

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/.


  Copyright 1993 David Metcalfe (davidprism.demon.co.uk)
and Copyright (C) 2007 Michael Kerrisk <mtk.manpagesgmail.com>

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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)