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authorEric Andersen <andersen@codepoet.org>2002-02-13 09:32:52 +0000
committerEric Andersen <andersen@codepoet.org>2002-02-13 09:32:52 +0000
commit80e6061ac5deca193759b979d34906bfc9b857ef (patch)
tree51f5c410f9313c6892b50f27321b64db8cfbd737 /test/pthread/ex5.c
parent98cba6e7dd947aec0d4cf6e61f2f31318ac919e1 (diff)
Several test suite updates. The testatexit, teston_exit, and
pthread tests were contributed by Stefan Soucek
Diffstat (limited to 'test/pthread/ex5.c')
-rw-r--r--test/pthread/ex5.c102
1 files changed, 102 insertions, 0 deletions
diff --git a/test/pthread/ex5.c b/test/pthread/ex5.c
new file mode 100644
index 000000000..475de0e0c
--- /dev/null
+++ b/test/pthread/ex5.c
@@ -0,0 +1,102 @@
+/* The classic producer-consumer example, implemented with semaphores.
+ 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"
+#include "semaphore.h"
+
+#define BUFFER_SIZE 16
+
+/* Circular buffer of integers. */
+
+struct prodcons {
+ int buffer[BUFFER_SIZE]; /* the actual data */
+ int readpos, writepos; /* positions for reading and writing */
+ sem_t sem_read; /* number of elements available for reading */
+ sem_t sem_write; /* number of locations available for writing */
+};
+
+/* Initialize a buffer */
+
+void init(struct prodcons * b)
+{
+ sem_init(&b->sem_write, 0, BUFFER_SIZE - 1);
+ sem_init(&b->sem_read, 0, 0);
+ b->readpos = 0;
+ b->writepos = 0;
+}
+
+/* Store an integer in the buffer */
+
+void put(struct prodcons * b, int data)
+{
+ /* Wait until buffer is not full */
+ sem_wait(&b->sem_write);
+ /* 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 contains one more element for reading */
+ sem_post(&b->sem_read);
+}
+
+/* Read and remove an integer from the buffer */
+
+int get(struct prodcons * b)
+{
+ int data;
+ /* Wait until buffer is not empty */
+ sem_wait(&b->sem_read);
+ /* 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 has now one more location for writing */
+ sem_post(&b->sem_write);
+ 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;
+
+void * producer(void * data)
+{
+ int n;
+ for (n = 0; n < 10000; n++) {
+ printf("%d --->\n", n);
+ put(&buffer, n);
+ }
+ put(&buffer, OVER);
+ return NULL;
+}
+
+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;
+}