Brief question about stdin

This is a discussion on Brief question about stdin within the C Programming forums, part of the General Programming Boards category; Hey, I was wondering: If I use "fclose(stdin)" to deactivate keyboard input, how can I "reopen" stdin? I believe it ...

  1. #1
    Dogbert B-Con's Avatar
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    Brief question about stdin

    Hey,

    I was wondering: If I use "fclose(stdin)" to deactivate keyboard input, how can I "reopen" stdin? I believe it has to do with fdopen().....?
    Last edited by B-Con; 05-30-2004 at 06:58 PM.
    "Cryptographically secure linear feedback shift register based stream ciphers" -- a phrase that'll get any party started.

  2. #2
    Obsessed with C chrismiceli's Avatar
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    Code:
    #include <stdio.h>
    
    int main(void) {
         int standard_input;
    
         standard_input = dup(STDIN_FILENO);
         fclose(stdin);
         fdopen(standard_input, "r");
         return 0;
    }
    dup:
    http://www.rt.com/man/dup.2.html
    fdopen:
    http://www.neosoft.com/neosoft/man/fdopen.3.html
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  3. #3
    & the hat of GPL slaying Thantos's Avatar
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    Do you ever take the time to try and research your questions C+++C_forever? Since these functions reside in stdio.h its a pretty good possiblity that they are standard.

  4. #4
    Dogbert B-Con's Avatar
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    I get it now..... Much thanx
    "Cryptographically secure linear feedback shift register based stream ciphers" -- a phrase that'll get any party started.

  5. #5
    Registered User pinko_liberal's Avatar
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    The following are not standard:
    dup
    fdopen

    and the macro STDIN_FILENO

    In ISO C, you interact with files through objects of type FILE *, there are no functions involving file descriptors, file handles etc.
    The one who says it cannot be done should never interrupt the one who is doing it.

  6. #6
    C++ Developer XSquared's Avatar
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    Quote Originally Posted by Thantos
    Do you ever take the time to try and research your questions C+++C_forever? Since these functions reside in stdio.h its a pretty good possiblity that they are standard.
    Do you ever take time to research your answers, Thantos? If you had even glanced at the links provided, you would've realized that the dup() and fdopen() functions are not ANSI-compliant, but POSIX-compliant.
    Naturally I didn't feel inspired enough to read all the links for you, since I already slaved away for long hours under a blistering sun pressing the search button after typing four whole words! - Quzah

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  7. #7
    & the hat of GPL slaying Thantos's Avatar
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    I looked up fdopen() on the man page and
    The fopen and freopen functions conform to ANSI X3.159-1989 (``ANSI C'').
    was tired and didn't realize that it didn't say fdopen(). Sorry was tired

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