Re: [KFUG] POSIX named semaphore

[Pyun YongHyeon <yongari@xxxxxxxxxxx>]

On Fri, May 14, 2004 at 05:27:07PM +0900, Seung-joo Lee wrote:
...
   sem_t *mutex;
   /* mutex = sem_open (SEM_NAME, O_CREAT | O_EXCL, FILE_MODE, 1); */
   /* mutex = sem_open (SEM_NAME, O_CREAT | O_EXCL); */
   mutex = sem_open (SEM_NAME, O_CREAT);
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
POSIX sem_open(3)을 살펴보세요.

     O_CREAT  Create the semaphore if it does not already exist.

              The third argument to the call to sem_open() must be of type
              mode_t and specifies the mode for the semaphore.  Only the
              S_IWUSR, S_IWGRP, and S_IWOTH bits are examined; it is not pos-
              sible to grant only ``read'' permission on a semaphore.  The
              mode is modified according to the process's file creation mask;
              see umask(2).

              The fourth argument must be an unsigned int and specifies the
              initial value for the semaphore, and must be no greater than
              SEM_VALUE_MAX.

   if ( mutex == SEM_FAILED )
...

-- 
Pyun YongHyeon <http://www.kr.freebsd.org/~yongari>
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