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putenv(S)


putenv -- change or add value to environment

Syntax

cc . . . -lc

#include stdlib.h>

int putenv (const char *string);

Description

string points to a string of the form name = value. The putenv function makes the value of the environment variable name equal to value by altering an existing variable or creating a new one. In either case, the string pointed to by string becomes part of the environment, so altering the string changes the environment. The space used by string is no longer used once a new string defining name is passed to putenv.

Diagnostics

The putenv function returns non-zero if it was unable to obtain enough space via malloc for an expanded environment, otherwise zero.

Warnings

The putenv function manipulates the environment pointed to by environ, and can be used in conjunction with getenv. However, envp (the third argument to main) is not changed. After putenv is called, environmental variables are not in alphabetical order.

A potential error is to call putenv with an automatic variable as the argument, then exit the calling function while string is still part of the environment.

This routine uses malloc(S) to enlarge the environment.

See also

environ(M), exec(S), getenv(S), malloc(S)

Standards conformance

putenv is conformant with:

X/Open Portability Guide, Issue 3, 1989 .


© 2003 Caldera International, Inc. All rights reserved.
SCO OpenServer Release 5.0.7 -- 11 February 2003