SemaphoreOperator.h

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#ifndef CARMA_UTIL_SEMAPHORE_OPS_H
#define CARMA_UTIL_SEMAPHORE_OPS_H

#include <sstream>

#include <fcntl.h>
#include <sys/types.h>
#include <sys/ipc.h>
#include <sys/sem.h>
#include <errno.h>

#define MAX_SEMS 250

namespace carma
{
  namespace util
  {
    class SemaphoreOperator
    {
      public:
        // TODO, have a static definition of semnums associated
        // with particular classes of Lock/Unlocks?
        SemaphoreOperator( int semnum );

        // TODO, Create framework to remove semaphore when not in use
        ~SemaphoreOperator() {};

        void Lock( struct timespec *timeout = NULL );
        void Unlock( struct timespec *timeout = NULL );

      private:

        static const key_t _key;
        int _semid; 
        int _semnum;

        struct sembuf _semop;

#if defined(__GNU_LIBRARY__) && !defined(_SEM_SEMUN_UNDEFINED)
        /* union semun is defined by including <sys/sem.h> */
#else
        /* according to X/OPEN we have to define it ourselves */
        union semun
        {
          int val;                  /* value for SETVAL */
          struct semid_ds *buf;     /* buffer for IPC_STAT, IPC_SET */
          unsigned short *array;    /* array for GETALL, SETALL */
          /* Linux specific part: */
          struct seminfo *__buf;    /* buffer for IPC_INFO */
        } _arg;
#endif // semun undefined
    };
  }
}



#endif // CARMA_UTIL_SEMAPHORE_OPS_H