Idle time of the user

This is a discussion on Idle time of the user within the Linux Programming forums, part of the Platform Specific Boards category; Hello together, i write a little programm, which checks, if a user is sitting in front of his computer or ...

  1. #1
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    Idle time of the user

    Hello together,
    i write a little programm, which checks, if a user is sitting in front of his computer or not.
    Now i want to find out, how long the user is idle, means how long no input has been made.
    Any suggestions how to solve this problem in C?
    I really dont have an idea where to start, maybe with the x-Window api or so...
    I hope you are able to help me. Thank you.

  2. #2
    Super Moderator Harbinger's Avatar
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    Try reading up on how screen savers work.

  3. #3
    junior member mix0matt's Avatar
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    Code:
    #include <sys/stat.h>
    #include <time.h>
    
    /*
     Take the difference between current time in seconds and access time of the
     users terminal device
    */
    
    int main(int argc, char *argv[])
    {
        struct stat f_info;
        /* terminal device for the user */
        const char *file_name = "/dev/pts/5";
        stat(file_name, &f_info);
    
        printf("%d\n", time(NULL) - f_info.st_atime);
        return 0;
    }
    THIS IS NOT JUST A CHRONICLING OF THINGS WE HAVE DONE IN THE PAST BUT OUR RISE TO POWER.

  4. #4
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    Thank you guys for your help and the piece of code.

    Is there also an other way than the one mix0matt described?
    How can i find out the terminal device of the user? Is it always /dev/pts/5 ?

  5. #5
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    I've found another solution, but there is a problem while i try to compile the source code.

    This is the code:
    Code:
    #include <stdio.h>
    #include <X11/Xlib.h>
    
    #include <X11/Xutil.h>
    #include <X11/extensions/scrnsaver.h>
    #include <gdk/gdkx.h>
    
    int main(void){
    	static XScreenSaverInfo *mit_info = NULL;
    	int event_base, error_base;
    		if (XScreenSaverQueryExtension(GDK_DISPLAY(), &event_base, &error_base)) {
    			mit_info = XScreenSaverAllocInfo();
    			XScreenSaverQueryInfo(GDK_DISPLAY(), GDK_ROOT_WINDOW(), mit_info);
    			printf("Idle Time: %i\n", mit_info->idle);
    		} else {
    			printf("No Display available");
    		}
    	return 0;
    }
    And this is my compilercall:
    Code:
     gcc -I/usr/X11R6/include -I/${GTK-DIR}/1.2.10/include/gtk-1.2 -I${GLIB-DIR}/1.2.10/include/glib-1.2 -I${GLIB-DIR}/lib/glib/include -L${GTK-DIR}/1.2.10/i686-pc-linux-gnuoldld/lib -L/usr/X11R6/lib -L/usr/X11R6/lib/X11 -lXss -lX11 -lgdk idle.c
    Now the compiler throws the following error:
    Code:
    /tmp/ccYXOUio.o(.text+0x33): In function `main':
    : undefined reference to `XScreenSaverQueryExtension'
    /tmp/ccYXOUio.o(.text+0x3c): In function `main':
    : undefined reference to `XScreenSaverAllocInfo'
    /tmp/ccYXOUio.o(.text+0x60): In function `main':
    : undefined reference to `XScreenSaverQueryInfo'
    collect2: ld returned 1 exit status
    Anybody got an idea why this happens?

  6. #6
    Super Moderator Harbinger's Avatar
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    > -lXss -lX11 -lgdk
    These go after .c files - otherwise the linker doesn't see any unresolved symbols when it gets to the libraries, therefore it doesn't think the libraries are necessary.

  7. #7
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    Hello,
    well, the compilation worked, an so does the code. But now, i've got another problem...
    These XScreenSaver functions only work, if the XscreenSaver extension is present.
    But i want code, which can run standalone, so i need to know how X gets the IdleTime.
    Does anybody know this? I dont want to read the whole source for xscreensaver to find out...

    This would help me very mutch. Thank you guys.

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