多个生产者，单个消费者，互斥锁

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#include <stdio.h> #include <stdlib.h> #include <pthread.h>   #define min(a,b) ((a)<(b)?(a):(b)) #define MAXNITEMS   1000000 #define MAXNTHREADS 10   int nitems; struct {     pthread_mutex_t mutex;     int buff[MAXNITEMS];     int nput;     int nval; }shared={     PTHREAD_MUTEX_INITIALIZER };   void *produce(void *), *consume(void *);   int main(int argc, char **argv) {     int i, nthreads, count[MAXNTHREADS];     pthread_t tid_produce[MAXNTHREADS], tid_consume;       if(argc!=3) {         fprintf(stderr, "usage: ./a.out <#items> <#threads>.\n");         exit(-1);     }     nitems=min(atoi(argv[1]), MAXNITEMS);     nthreads=min(atoi(argv[2]), MAXNTHREADS);       pthread_setconcurrency(nthreads);       for(i=0;i<nthreads;i++) {         count[i]=0;         pthread_create(&tid_produce[i], NULL, produce, &count[i]);     }       for(i=0;i<nthreads;i++) {         pthread_join(tid_produce[i], NULL);         printf("count[%d]=%d\n", i, count[i]);     }       pthread_create(&tid_consume, NULL, consume, NULL);     pthread_join(tid_consume, NULL);       exit(0); }   void *produce(void *arg) {     for(;;) {         pthread_mutex_lock(&shared.mutex);         if(shared.nput>=nitems) {             pthread_mutex_unlock(&shared.mutex);             return NULL;         }         shared.buff[shared.nput]=shared.nval;         shared.nput++;         shared.nval++;         pthread_mutex_unlock(&shared.mutex);         *((int *)arg)+=1;     } }   void *consume(void *arg) {     int i;     for(i=0;i<nitems;i++) {         if(shared.buff[i]!=i) {             printf("buff[%d]=%d\n", i, shared.buff[i]);         }     }     return NULL; }

结果如下：

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$ gcc prodcons.c -pthread $ ./a.out 10000000 5 count[0]=253230 count[1]=285783 count[2]=129999 count[3]=157355 count[4]=173633