semext.h

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#ifndef SEM_H
#define SEM_H
 
#include <sys/sem.h>
#include "hdp.h"
#include "dbc.h"
 
#define semup(semid, index) \
   ({\
      struct sembuf op = {(unsigned short)(index), 1, 0}; \
      MO(semop(semid, &op, 1)); \
   })
 
#define semdown(semid, index) \
   ({\
      struct sembuf op = {(unsigned short)(index), -1, 0}; \
      MO(semop(semid, &op, 1)); \
   })
 
#define semdown2(semid, index1, index2) \
   ({\
      require (index1 != index2, "both semaphore indexes are equal!"); \
      struct sembuf ops[2] = {{(unsigned short)(index1), -1, 0}, {(unsigned short)(index2), -1, 0}}; \
      MO(semop(semid, ops, 2)); \
   })
 
#define semupdown(semid, up_index, down_index) \
   ({\
      require (up_index != down_index, "both semaphore indexes are equal!"); \
      struct sembuf ops[2] = {{(unsigned short)(up_index), 1, 0}, {(unsigned short)(down_index), -1, 0}}; \
      MO(semop(semid, ops, 2)); \
   })
 
#define semsetval(semid, index, value) \
   ({\
      union semun { \
         int val; \
         struct semid_ds *buf; \
         unsigned short *array; \
      } semopts; \
      semopts.val = value; \
      MO(semctl(semid, index, SETVAL, semopts)); \
   })
 
#endif
 
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