Question about closeing and opening stdin

From: Michael C. Shultz (ringworm01_at_gmail.com)
Date: 11/22/05

  • Next message: Kris Kennaway: "Re: Core dump after RELENG_5_4 to RELENG_6_0" 
    To: freebsd-hackers@freebsd.org
Date: Tue, 22 Nov 2005 10:50:48 -0800

    How do I close then open stdin and keep it set to the same terminal
    as when it was closed? Everything I've tried so far has met with failure
    accept this works sort of and I don't get why:

    signal( SIGALRM, MGPMrTimer );
    alarm( 300 ); /* time out in 5 minutes */
    answer = getc(stdin);

    the signal handler just closes descriptor 0 if a timeout occrs:

    close( 0 )

    then to reset stdin I tried this:

    stdinFileDescriptor = open( "/dev/tty", O_RDWR ) )
    stdin = fdopen( stdinFileDescriptor, "r" );

    and it works in this instance of the program, but
    if a second instance is started the second instance can't
    close stdin.

    I got the above idea from google, what I don't understand though
    is there is no /dev/tty! So anyone have any suggested books
    I might read or tips so I can learn how to do this right, and understand
    why it works?

    Thank you,

    Mike
    _______________________________________________
    freebsd-hackers@freebsd.org mailing list
    http://lists.freebsd.org/mailman/listinfo/freebsd-hackers
    To unsubscribe, send any mail to "freebsd-hackers-unsubscribe@freebsd.org"

  • Next message: Kris Kennaway: "Re: Core dump after RELENG_5_4 to RELENG_6_0"

    Relevant Pages

    • Re: Question about closeing and opening stdin
      ... >> How do I close then open stdin and keep it set to the same terminal ... >> if a second instance is started the second instance can't ... >> close stdin. ... fclose(local_stdin); ...
      (freebsd-hackers)
    • Re: Question about closeing and opening stdin
      ... > How do I close then open stdin and keep it set to the same terminal ... > the signal handler just closes descriptor 0 if a timeout occrs: ... > if a second instance is started the second instance can't ...
      (freebsd-hackers)
    • Re: signal(SIGCHLD, Handler) Problem
      ... So your question is really "why does fgets(..., stdin) ... because you didn't set your signal handler ... switch (pid) { ... fprintf(stderr, "main returns, errno %d (%s)\n", errno, strerror); ...
      (comp.os.linux.development.system)
    • Re: signal(SIGCHLD, Handler) Problem
      ... So your question is really "why does fgets(..., stdin) ... because you didn't set your signal handler ... switch (pid) { ... fprintf(stderr, "main returns, errno %d (%s)\n", errno, ...
      (comp.os.linux.development.system)
    • Re: How to to kill a c program at the exit of my gui?
      ... > is EOF of stdin, ... So I want the recv program to know this ... and use the corresponding signal handler to kill itself. ...
      (comp.lang.tcl)