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-rw-r--r--test/pthread/ex2.c113
1 files changed, 0 insertions, 113 deletions
diff --git a/test/pthread/ex2.c b/test/pthread/ex2.c
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--- a/test/pthread/ex2.c
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-/* The classic producer-consumer example.
- Illustrates mutexes and conditions.
- All integers between 0 and 9999 should be printed exactly twice,
- once to the right of the arrow and once to the left. */
-
-#include <stdio.h>
-#include "pthread.h"
-
-#define BUFFER_SIZE 16
-
-/* Circular buffer of integers. */
-
-struct prodcons {
- int buffer[BUFFER_SIZE]; /* the actual data */
- pthread_mutex_t lock; /* mutex ensuring exclusive access to buffer */
- int readpos, writepos; /* positions for reading and writing */
- pthread_cond_t notempty; /* signaled when buffer is not empty */
- pthread_cond_t notfull; /* signaled when buffer is not full */
-};
-
-/* Initialize a buffer */
-
-static void init(struct prodcons * b)
-{
- pthread_mutex_init(&b->lock, NULL);
- pthread_cond_init(&b->notempty, NULL);
- pthread_cond_init(&b->notfull, NULL);
- b->readpos = 0;
- b->writepos = 0;
-}
-
-/* Store an integer in the buffer */
-
-static void put(struct prodcons * b, int data)
-{
- pthread_mutex_lock(&b->lock);
- /* Wait until buffer is not full */
- while ((b->writepos + 1) % BUFFER_SIZE == b->readpos) {
- pthread_cond_wait(&b->notfull, &b->lock);
- /* pthread_cond_wait reacquired b->lock before returning */
- }
- /* Write the data and advance write pointer */
- b->buffer[b->writepos] = data;
- b->writepos++;
- if (b->writepos >= BUFFER_SIZE) b->writepos = 0;
- /* Signal that the buffer is now not empty */
- pthread_cond_signal(&b->notempty);
- pthread_mutex_unlock(&b->lock);
-}
-
-/* Read and remove an integer from the buffer */
-
-static int get(struct prodcons * b)
-{
- int data;
- pthread_mutex_lock(&b->lock);
- /* Wait until buffer is not empty */
- while (b->writepos == b->readpos) {
- pthread_cond_wait(&b->notempty, &b->lock);
- }
- /* Read the data and advance read pointer */
- data = b->buffer[b->readpos];
- b->readpos++;
- if (b->readpos >= BUFFER_SIZE) b->readpos = 0;
- /* Signal that the buffer is now not full */
- pthread_cond_signal(&b->notfull);
- pthread_mutex_unlock(&b->lock);
- return data;
-}
-
-/* A test program: one thread inserts integers from 1 to 10000,
- the other reads them and prints them. */
-
-#define OVER (-1)
-
-struct prodcons buffer;
-
-static void * producer(void * data)
-{
- int n;
- for (n = 0; n < 10000; n++) {
- printf("%d --->\n", n);
- put(&buffer, n);
- }
- put(&buffer, OVER);
- return NULL;
-}
-
-static void * consumer(void * data)
-{
- int d;
- while (1) {
- d = get(&buffer);
- if (d == OVER) break;
- printf("---> %d\n", d);
- }
- return NULL;
-}
-
-int main(void)
-{
- pthread_t th_a, th_b;
- void * retval;
-
- init(&buffer);
- /* Create the threads */
- pthread_create(&th_a, NULL, producer, 0);
- pthread_create(&th_b, NULL, consumer, 0);
- /* Wait until producer and consumer finish. */
- pthread_join(th_a, &retval);
- pthread_join(th_b, &retval);
- return 0;
-}