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                                                                putenv(3)



        _________________________________________________________________
        putenv                                                 Subroutine
        change or add value to environment
        _________________________________________________________________


        SYNTAX

        int putenv (string)
        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.
        The space used by string is no longer used once a new string-
        defining name is passed to putenv.


        DIAGNOSTICS

        Putenv returns non-zero if it couldn't obtain enough space via
        malloc for an expanded environment.  Otherwise, it returns zero.


        SEE ALSO

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


        WARNINGS

        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
        alphabetical order.
        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 the environment.







        DG/UX 4.00                                                 Page 1
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