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[2] | 1 | /* Copyright (C) 2009 by Mattia Monga <mattia.monga@unimi.it> */
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| 2 | /* $Id$ */
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| 3 |
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| 4 | #include <unistd.h>
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| 5 | #include <stdio.h>
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| 6 | #include <stdlib.h>
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| 7 | #include <signal.h>
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| 8 | #include <sched.h>
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| 9 | #include <semaphore.h>
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| 10 |
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[25] | 11 | void down(sem_t *s){
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[2] | 12 | if (sem_wait(s) < 0){
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| 13 | perror("Errore semaforo (down)");
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| 14 | exit(1);
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| 15 | }
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| 16 | }
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| 17 |
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[25] | 18 | void up(sem_t *s){
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[2] | 19 | if (sem_post(s) < 0){
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| 20 | perror("Errore semaforo (up)");
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| 21 | exit(1);
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| 22 | }
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| 23 | }
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| 24 |
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[25] | 25 | int shared = 0;
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| 26 | pthread_t p1, p2;
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| 27 | sem_t ss;
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| 28 |
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| 29 | void* run(void* s){
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| 30 | while (down(&ss),
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| 31 | shared < 10) {
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[2] | 32 | sleep(1);
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[25] | 33 | printf("Processo thread (%p). s = %d\n",
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| 34 | pthread_self(), shared);
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| 35 | if (!(shared < 10)){
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[2] | 36 | printf("Corsa critica!!!!\n");
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| 37 | abort();
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| 38 | }
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[25] | 39 | shared += 1;
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| 40 | up(&ss);
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| 41 | pthread_yield();
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[2] | 42 | }
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[25] | 43 | up(&ss);
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| 44 | return NULL;
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[2] | 45 | }
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| 46 |
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| 47 |
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[25] | 48 |
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[2] | 49 | int main(void){
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| 50 |
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[25] | 51 | if (sem_init(&ss,
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[2] | 52 | 0 /* thread local semaphore */,
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[25] | 53 | 1 /* init value */
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[2] | 54 | ) < 0){
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| 55 | perror("Errore semaforo");
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| 56 | exit(1);
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| 57 | }
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| 58 |
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[25] | 59 | pthread_create(&p1, NULL, run, NULL);
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| 60 | pthread_create(&p2, NULL, run, NULL);
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[2] | 61 |
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[25] | 62 | pthread_join(p1, NULL);
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| 63 | pthread_join(p2, NULL);
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| 64 |
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| 65 | sem_destroy(&ss);
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| 66 |
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[2] | 67 | return 0;
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| 68 | }
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| 69 |
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| 70 |
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| 71 |
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| 72 |
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| 73 |
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| 74 |
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| 75 |
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| 76 | /* Local Variables: */
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| 77 | /* compile-command: "make -k " */
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| 78 | /* End: */
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