Problem About how to use shared posix semaphore

From: Gary Li-126 (liguoqiang_0121_at_126.com)
Date: 09/29/05

  • Next message: Gavin Atkinson: "Re: Problem About how to use shared posix semaphore" 
    To: <freebsd-stable@freebsd.org>
Date: Thu, 29 Sep 2005 20:47:09 +0800

    Hi,
        I always get the error message:"Operation not permitted" When I use sem_init set pshared argument equal 1. Compiling as : "gcc -o sem_test sem_test.c -lc_r". My freebsd ver is release 5.4 p6.
        Test code appear below:
          1 #include <sys/types.h>
          2 #include <string.h>
          3 #include <stdio.h>
          4 #include <sys/stat.h>
          5 #include <unistd.h>
          6 #include <fcntl.h>
          7 #include <errno.h>
          8 #include <pthread.h>
          9 #include <semaphore.h>
         10
         11 int main(int argc, char ** argv)
         12 {
         13 sem_t mutex;
         14 if (-1 == sem_init (&mutex, 1, 1)) {
         15 printf("sem init error:%s\n", strerror(errno));
         16 exit(0);
         17 }
         18 sem_wait (&mutex);
         19 printf("sem wait ok:\n");
         20 sem_post (&mutex);
         21 sem_destroy (&mutex);
         22 return 0;
         23 }

    Best regards,
    Gary Li

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  • Next message: Gavin Atkinson: "Re: Problem About how to use shared posix semaphore"