44 lines
1.1 KiB
C
44 lines
1.1 KiB
C
#include <stdio.h>
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#include <pthread.h>
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#include <semaphore.h>
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#include <fcntl.h>
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#include <stdatomic.h>
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atomic_int counter = 0; // shared resource
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sem_t *semaphore; // semaphore declaration
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void* increment(void* arg) {
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for (int i = 0; i < 100000; i++) {
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sem_wait(semaphore); // lock
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atomic_fetch_add(&counter, 1); // critical section
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sem_post(semaphore); // unlock
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}
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return NULL;
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}
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int main() {
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pthread_t t1, t2, t3, t4;
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// MacOS specific semaphore definition.
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semaphore = sem_open("/mysem", O_CREAT, 0644, 1);
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if (semaphore == SEM_FAILED) {
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perror("sem_open failed");
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return 1;
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}
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pthread_create(&t1, NULL, increment, NULL);
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pthread_create(&t2, NULL, increment, NULL);
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pthread_create(&t3, NULL, increment, NULL);
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pthread_create(&t4, NULL, increment, NULL);
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pthread_join(t1, NULL);
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pthread_join(t2, NULL);
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pthread_join(t3, NULL);
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pthread_join(t4, NULL);
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sem_close(semaphore);
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sem_unlink("/mysem");
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printf("Final Counter Value (with semaphores): %d\n", atomic_load(&counter));
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return 0;
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}
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