Can't write to stdscr

This is a discussion on Can't write to stdscr within the Linux Programming forums, part of the Platform Specific Boards category; When I today began learning ncurses API, I ran into a problem. I can't write into stdscr. I wrote few ...

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    Can't write to stdscr

    When I today began learning ncurses API, I ran into a problem. I can't write into stdscr.
    I wrote few short programs, but none of them did work. I tried to write with printw(), mvprintw(), addch() and mvaddch() functions, but they didn't work. I tried to also write with printf() function in ncurses mode, but nothing happent. Writing with printf() while not in ncurses mode works fine.
    Version of ncurses library I'm using is 5.6. OS I'm using is Xubuntu GNU/Linux. Terminal emulator is Xfce-Terminal. Comipler is gcc 4.1.2. If someone needs more information, I can tell, or if I don't know, try to find out it.
    Last edited by fronty; 07-15-2007 at 11:20 AM.

  2. #2
    Captain Crash brewbuck's Avatar
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    Quote Originally Posted by fronty View Post
    When I today began learning ncurses API, I ran into a problem. I can't write into stdscr.
    I wrote few short programs, but none of them did work. I tried to write with printw(), mvprintw(), addch() and mvaddch() functions, but they didn't work. I tried to also write with printf() function in ncurses mode, but nothing happent. Writing with printf() while not in ncurses mode works fine.
    Version of ncurses library I'm using is 5.6. OS I'm using is Xubuntu GNU/Linux. Terminal emulator is Xfce-Terminal. Comipler is gcc 4.1.2. If someone needs more information, I can tell, or if I don't know, try to find out it.
    Probably ncurses closes all funny file descriptors, including stdscr, whatever that is. Just use stdout.

  3. #3
    and the hat of int overfl Salem's Avatar
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    Do basic ncurses programs work for you?
    http://tldp.org/HOWTO/NCURSES-Programming-HOWTO/
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.
    I support http://www.ukip.org/ as the first necessary step to a free Europe.

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    int x = *((int *) NULL); Cactus_Hugger's Avatar
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    Have you called initscr() ? Are you calling refresh() ? Could you post a minimal not-working example?
    long time; /* know C? */
    Unprecedented performance: Nothing ever ran this slow before.
    Any sufficiently advanced bug is indistinguishable from a feature.
    Real Programmers confuse Halloween and Christmas, because dec 25 == oct 31.
    The best way to accelerate an IBM is at 9.8 m/s/s.
    recursion (re - cur' - zhun) n. 1. (see recursion)

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    Salem: No, they don't work.
    Cactus_Hugger: Yes, I have called initscr() and refreshed window after printing.
    And one minimal example:
    Code:
    /* Hello, World */
    
    #include <ncurses.h>
    
    int main(void) {
        initscr();
    
        printw("Hello, World!");
        refresh();
    
        endwin();
        return 0;
    }

  6. #6
    Woof, woof! zacs7's Avatar
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    fronty, got the ncurses library installed (ie not just ncurses-devel)

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    I compiled only source package I found for version 5.6, so I think I have whole library installed. :/

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    int x = *((int *) NULL); Cactus_Hugger's Avatar
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    Your minimal sample may be running too quickly. Place a getch() right before the endwin() call.
    long time; /* know C? */
    Unprecedented performance: Nothing ever ran this slow before.
    Any sufficiently advanced bug is indistinguishable from a feature.
    Real Programmers confuse Halloween and Christmas, because dec 25 == oct 31.
    The best way to accelerate an IBM is at 9.8 m/s/s.
    recursion (re - cur' - zhun) n. 1. (see recursion)

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    :/ Doesn't work. :/
    It seems to me it writes to it, but somehow it doesn't show it on teminal.

  10. #10
    and the hat of int overfl Salem's Avatar
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    IIRC, there are a multitude of different terminal emulators on most Linux distros.
    Have you tried other ones?
    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.
    I support http://www.ukip.org/ as the first necessary step to a free Europe.

  11. #11
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    Tried with xterm, and with it works. Must try to find out why it didn't work with Xfce-terminal.

  12. #12
    and the hat of int overfl Salem's Avatar
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    If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
    If at first you don't succeed, try writing your phone number on the exam paper.
    I support http://www.ukip.org/ as the first necessary step to a free Europe.

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