aboutsummaryrefslogtreecommitdiff
path: root/linuxthreads/Examples/ex2.c
diff options
context:
space:
mode:
Diffstat (limited to 'linuxthreads/Examples/ex2.c')
-rw-r--r--linuxthreads/Examples/ex2.c124
1 files changed, 0 insertions, 124 deletions
diff --git a/linuxthreads/Examples/ex2.c b/linuxthreads/Examples/ex2.c
deleted file mode 100644
index f2556a4206..0000000000
--- a/linuxthreads/Examples/ex2.c
+++ /dev/null
@@ -1,124 +0,0 @@
-/* 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;
-}