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https://github.com/ada-dmitry/prog.l_ada.git
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63 lines
1.3 KiB
C
63 lines
1.3 KiB
C
#include <stdio.h>
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#include <stdlib.h>
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#include <sys/ipc.h>
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#include <sys/sem.h>
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#include <sys/shm.h>
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#include "svshm_string.h"
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int main(void)
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{
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int semid, shmid;
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char *addr;
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union semun arg, dummy;
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struct sembuf sop;
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/* Create shared memory and semaphore set containing one
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semaphore. */
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shmid = shmget(IPC_PRIVATE, MEM_SIZE, IPC_CREAT | 0600);
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if (shmid == -1)
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errExit("shmget");
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semid = semget(IPC_PRIVATE, 1, IPC_CREAT | 0600);
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if (semid == -1)
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errExit("semget");
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/* Attach shared memory into our address space. */
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addr = shmat(shmid, NULL, SHM_RDONLY);
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if (addr == (void *)-1)
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errExit("shmat");
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/* Initialize semaphore 0 in set with value 1. */
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arg.val = 1;
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if (semctl(semid, 0, SETVAL, arg) == -1)
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errExit("semctl");
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printf("shmid = %d; semid = %d\n", shmid, semid);
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/* Wait for semaphore value to become 0. */
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sop.sem_num = 0;
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sop.sem_op = 0;
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sop.sem_flg = 0;
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if (semop(semid, &sop, 1) == -1)
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errExit("semop");
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/* Print the string from shared memory. */
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printf("%s\n", addr);
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/* Remove shared memory and semaphore set. */
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if (shmctl(shmid, IPC_RMID, NULL) == -1)
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errExit("shmctl");
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if (semctl(semid, 0, IPC_RMID, dummy) == -1)
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errExit("semctl");
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exit(EXIT_SUCCESS);
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}
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