diff options
author | Eric Andersen <andersen@codepoet.org> | 2002-02-13 09:32:52 +0000 |
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committer | Eric Andersen <andersen@codepoet.org> | 2002-02-13 09:32:52 +0000 |
commit | 80e6061ac5deca193759b979d34906bfc9b857ef (patch) | |
tree | 51f5c410f9313c6892b50f27321b64db8cfbd737 /test/pthread/ex5.c | |
parent | 98cba6e7dd947aec0d4cf6e61f2f31318ac919e1 (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.c | 102 |
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; +} |