PUTENV(3) Library Functions Manual PUTENV(3)
putenv - change or add value to environment
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. The space used by string is no
longer used once a new string-defining name is passed to putenv().
execve(2V), getenv(3V), malloc(3V), environ(5V).
putenv() returns non-zero if it was unable to obtain enough space using
malloc(3V) for an expanded environment, otherwise zero.
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(3V) to enlarge the environment.
After putenv() is called, environmental variables are not in alphabeti-
A potential error is to call putenv() with an automatic variable as the
argument, then exit the calling function while string is still part of
21 February 1989 PUTENV(3)