SETENV(3C) Standard C Library Functions SETENV(3C)
NAME
setenv - add or change environment variable
SYNOPSIS
#include <stdlib.h>
int setenv(
const char *envname,
const char *envval,
int overwrite);
DESCRIPTION
The
setenv() function updates or adds a variable in the environment
of the calling process. The
envname argument points to a string
containing the name of an environment variable to be added or
altered. The environment variable is set to the value to which
envval points. The function fails if
envname points to a string which
contains an '=' character. If the environment variable named by
envname already exists and the value of
overwrite is non-zero, the
function returns successfully and the environment is updated. If the
environment variable named by
envname already exists and the value of
overwrite is zero, the function returns successfully and the
environment remains unchanged.
If the application modifies
environ or the pointers to which it
points, the behavior of
setenv() is undefined. The
setenv() function
updates the list of pointers to which
environ points.
The strings described by
envname and
envval are copied by this
function.
RETURN VALUES
Upon successful completion, 0 is returned. Otherwise, -1 is returned,
errno set to indicate the error, and the environment is left
unchanged.
ERRORS
The
setenv() function will fail if:
EINVAL The
envname argument is a null pointer, points to an empty
string, or points to a string containing an '=' character.
ENOMEM Insufficient memory was available to add a variable or its
value to the environment.
ATTRIBUTES
See
attributes(7) for descriptions of the following attributes:
+--------------------+-----------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+--------------------+-----------------+
|Interface Stability | Standard |
+--------------------+-----------------+
|MT-Level | MT-Safe |
+--------------------+-----------------+
SEE ALSO
getenv(3C),
unsetenv(3C),
attributes(7),
standards(7) March 31, 2002 SETENV(3C)
