Re: XForms: fl_exe_command

From: Steve Lamont (
Date: Thu Mar 16 2000 - 09:42:31 EST

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    # To subscribers of the xforms list from (Steve Lamont) :

    > I'm trying to create an mpeg movie with "mpeg_encode", from flimage.
    > I created a new process with fl_exe_command("mpeg_encode",FALSE)
    > and i would like to dump my images in its "stdin"...

    If all you want to do is to spawn a process and write to it, you don't
    necessarily need to use fl_exe_command() or its ilk -- you can use
    plain old popen() and pclose().

        FILE *f;

        f = popen( "myprocess", "w" );

        fprintf( f, "hello there!\n" );

        pclose( f );

    Refer to your system's man pages for details.

    If your process displays some sort of useful information to standard
    output or standard error, you can use fl_oppen() and fl_pclose(),
    which are XForms wrappers.

        FILE *f;

        fl_show_command_log( FL_FULLBORDER );

        f = fl_popen( "myprocess", "w" );

        fprintf( f, "hello xforms!\n" );

        fl_pclose( f );

    This is discussed in the Command Log section of the XForms manual.

    [An aside to TC -- the LaTeX in that section is a bit garbled, at
    least in my copy of the manual. Has it been fixed?]A

    > I'm not very familiar with fork and this kind of stuff...

    The Richard W. Stevens book _Advanced Programming in the UNIX
    Environment_ is an excellent reference.

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