setenv(3C) Standard C Library Functions setenv(3C)NAMEsetenv - 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 contain‐
ing 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 success‐
fully and the environment is updated. If the environment variable named
by envname already exists and the value of overwrite is zero, the func‐
tion 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 func‐
tion.
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 ALSOgetenv(3C), unsetenv(3C), attributes(5), standards(5)SunOS 5.10 31 Mar 2002 setenv(3C)