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 con-
taining 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 vari-
able 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(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Interface Stability |Standard |
+-----------------------------+-----------------------------+
|MT-Level |MT-Safe |
+-----------------------------+-----------------------------+
SEE ALSO
getenv(3C), unsetenv(3C), attributes(5), standards(5)
SunOS 5.10 31 Mar 2002 setenv(3C)