putenv(3C)                                                       putenv(3C)

NAME
     putenv - change/add environment variables

SYNOPSIS
     #include <stdlib.h>

     int putenv(const char *string);

DESCRIPTION
     string points to a string of the form name=value. putenv() makes the
     value of the environment variable name equal to value by altering an
     existing variable or creating a new one. In either case, the string
     pointed to by string becomes part of the environment, so altering the
     string will change the environment. putenv() does not set up a copy of
     string. string should be declared static if it is declared within a
     function. The space used by string is no longer used once a new
     string, defined by name, is passed to putenv().

RESULT
     putenv() returns non-zero if it was unable to obtain enough space via
     malloc() for an expanded environment, otherwise zero.

NOTES
     putenv() manipulates the environment pointed to by environ, and can be
     used in conjunction with getenv(). However, envp (the third argument
     to main) is not changed.

     This routine uses malloc(3C) to enlarge the environment.

     After putenv() is called, environmental variables are not in alphabet-
     ical order. A potential error is to call the function putenv() with a
     pointer to an auto variable as the argument and to then exit the cal-
     ling function while string is still part of the environment.

SEE ALSO
     exec(2), getenv(3C), malloc(3C), environ(5).



















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