PUTENV(3C)           INTERACTIVE UNIX System           PUTENV(3C)



          NAME
               putenv - change or add value to environment

          SYNOPSIS
               int putenv (string)
               char *string;

          DESCRIPTION
               String points to a string of the form ``name=value.''  The
               putenv function 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.

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

          DIAGNOSTICS
               The putenv function returns non-zero if it was unable to
               obtain enough space via malloc for an expanded environment,
               otherwise zero.

          WARNINGS
               The putenv function 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
               alphabetical order.
               A potential error is to call putenv with an automatic vari-
               able as the argument, then exit the calling function while
               string is still part of the environment.




















          Rev. C Software Development Set                            Page 1