Header files
#include <sys/types.h>
#include <stdlib.h>
#include <sys/ipc.h>
#include <sys/sem.h>
#include <sys/shm.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <errno.h>
#include <string.h>
#include <stdio.h>
#define SHM_KEY 123
#define SEM_KEY 456
#define PLAIN 0
#define CHOC 1 const int shared_segment_size = 0x6400; union semun { int val; struct semid_ds *buf; unsigned short int *array; struct seminfo *__buf;
};

Create sem
#include "my_ipc.h" int main( int argc, char *argv[])
{
int sem_id, proj_id; if ( (sem_id = semget (SEM_KEY, 2, IPC_CREAT | IPC_EXCL | 0600 )) == -1 ) {perror ("Unable to create semaphore"); exit(5); }printf ("sem_id is %d\n", sem_id ); semaphore_initialize (sem_id);
}int semaphore_initialize (int semid)
{ union semun argument; unsigned short values[2]; values[PLAIN] = 0; values[CHOC] = 0; argument.array = values; return semctl (semid, 0, SETALL, argument);
}

Producer_consumer
#include "my_ipc.h" int main()
{ int sem_id, user_type, plain, choc; char *shared_memory; if ( (sem_id = semget (SEM_KEY, 1, 0600 )) == -1 ) { perror ("Unable to get hold of the semaphore "); exit(5); } printf ("Enter 0 if you are a producer or 1 if you are a consumer : "); scanf ("%d", &user_type ); if ( user_type ) { printf ("How many plain doughnuts you want to consume : "); scanf ("%d", &plain ); printf ("How many chocolate doughnuts you want to consume : "); scanf ("%d", &choc ); semaphore_wait (sem_id, plain, choc); printf ("Process %d done eating doughnuts\n", getpid()); }else { printf ("How many plain doughnuts you want to produce : "); scanf ("%d", &plain ); printf ("How many chocolate doughnuts you want to produce : "); scanf