Content-type: text/html Man page of putenv

putenv

Section: C Library Functions (3)
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NAME

putenv - Sets an environment variable  

LIBRARY

Standard C Library (libc.so, libc.a)  

SYNOPSIS

#include <stdlib.h>

int putenv(
        const char *string);  

STANDARDS

Interfaces documented on this reference page conform to industry standards as follows:

putenv():  XPG4, XPG4-UNIX

Refer to the standards(5) reference page for more information about industry standards and associated tags.  

PARAMETERS

Points to a name=value string.  

DESCRIPTION

The putenv() function sets the value of an environment variable by altering an existing variable or by creating a new one. The new environment variable remains in effect even after the program setting it is exited.

The string parameter points to a string of the form "name=value", where name is the environment variable and value is the new value for it.  

NOTES

The putenv() function manipulates the environ external variable, and it can be used in conjunction with the getenv() function. However, the third parameter to the main function (the environment pointer) is not changed.

The putenv() function uses the malloc() function to enlarge the environment.

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

RETURN VALUES

Upon successful completion, a value of 0 (zero) is returned. If the malloc() function is unable to obtain sufficient space to expand the environment, the putenv() function returns a nonzero value.  

RELATED INFORMATION

Functions: clearenv(3), exec(2), getenv(3), malloc(3)

Standards: standards(5) delim off


 

Index

NAME
LIBRARY
SYNOPSIS
STANDARDS
PARAMETERS
DESCRIPTION
NOTES
RETURN VALUES
RELATED INFORMATION

This document was created by man2html, using the manual pages.
Time: 02:41:26 GMT, October 02, 2010