Re: How do you use 'cdrw' within an application?

From: Logan Shaw (lshaw-usenet_at_austin.rr.com)
Date: 12/02/03

  • Next message: Joerg Schilling: "Re: How do you use 'cdrw' within an application?" 
    Date: Mon, 01 Dec 2003 23:44:35 GMT

    M Sudderth wrote:

    > I'm using a Plextor PX-W1210TSE CD-RW drive on a Solaris 8 system.
    >
    > I'm writing an application in C++ and need to be able to burn
    > files/image to a CD from within the application.
    >
    > 'cdrw' may be able to be used, but it's a command-line command. I may
    > be able to use the "system" operation:
    > i.e.
    > system("mkisofs -r <directory> 2>/tmp/cdrw_log | cdrw -i -p 4");
    >
    > But errors can not be returned to the calling application. This will
    > only
    > work in the "happy day" scenario.

    The proper thing to do would be to create a pipe using pipe().
    Then, for mkisofs, do a fork() and connect the child process's
    input to /dev/null and stdout to the input end of the pipe
    (and close the output end of the pipe in that process). Then
    do something similar for cdrw: fork(), open() of /dev/null
    and replace stdout with that (using dup2() after closing stdout,
    if I recall correctly), close the input end of the pipe, connect
    stdin to the output end of the pipe, then exec() cdrw. Finally,
    in the parent, close both ends of the pipe (since only the
    children need it), and wait() on both the children. The wait()
    call will allow you to retrieve the exit code of both child
    processes, and this will allow you to determine if the process
    worked or not.

    Where you send stderr is another question. You could send it
    to /dev/null or to a log file or to a second pipe that your
    application reads if you want.

    Alternately, write a shell script that does the right thing
    given the desired parameters, checks the result code of both
    processes in the pipe, and returns a single exit code indicating
    failure of success. Then just fork() and exec() that shell
    script. Or popen() the shell script and make it spit out a
    summary of what happened on its stdout, then read the summary
    via pipe.

       - Logan

  • Next message: Joerg Schilling: "Re: How do you use 'cdrw' within an application?"

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