putenv(3)putenv(3)NAMEputenv - Sets an environment variable
SYNOPSIS
#include <stdlib.h>
int putenv(
const char *string );
The following syntax is for XSH5.0-compliant interfaces: #include
<stdlib.h>
int putenv(
char *string );
LIBRARY
Standard C Library (libc)
STANDARDS
Interfaces documented on this reference page conform to industry stan‐
dards as follows:
putenv(): XSH4.0, XSH4.2, XSH5.0, POSIX.1
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 envi‐
ronment 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 envi‐
ronment.
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.
SEE ALSO
Functions: clearenv(3), exec(2), getenv(3), malloc(3)
Standards: standards(5)putenv(3)
