生产者消费者

#include<stdio.h>#include<unistd.h>#include<stdlib.h>#include<fcntl.h>#include<string.h>#include<pthread.h>#include<sys/mman.h>#include<sys/types.h>#define BSIZE 10typedef struct buffer_s {    char buf[BSIZE];    int occupied;    int nextin;    int nextout;    pthread_mutex_t mutex;    pthread_cond_t  more;    pthread_cond_t  less;}buffer_t;void producer(buffer_t *b, char item) {    pthread_mutex_lock(&b->mutex);    while (b->occupied >= BSIZE)        pthread_cond_wait(&b->less, &b->mutex);    b->buf[b->nextin] = item;    b->nextin++;    b->nextin %= BSIZE;    b->occupied++;    pthread_cond_signal(&b->more);    pthread_mutex_unlock(&b->mutex);}char consumer(buffer_t *b) {    char item;    pthread_mutex_lock(&b->mutex);    while (b->occupied <= 0)        pthread_cond_wait(&b->more, &b->mutex);    item = b->buf[b->nextout];    b->nextout++;    b->nextout %= BSIZE;    b->occupied--;    pthread_cond_signal(&b->less);    pthread_mutex_unlock(&b->mutex);    return item;}void produce_driver(buffer_t *b) {    char item;    while (1) {        item = getchar();        if ('#' == item) {            producer(b, '\0');            break;        } else {            producer(b, (char)item);        }    }}void consume_driver(buffer_t *b) {    char item;    while (1) {        item = consumer(b);        if ('\0' == item)            break;        putchar(item);    }}int main(int argc, char *argv[]) {    int zfd;    buffer_t *buffer;    pthread_mutexattr_t mattr;    pthread_condattr_t cattr_less, cattr_more;    zfd = open("/dev/zero", O_RDWR);    buffer = (buffer_t*)mmap(NULL, sizeof(buffer_t), PROT_READ|PROT_WRITE, MAP_SHARED, zfd, 0);    buffer->occupied = buffer->nextin = buffer->nextout = 0;    pthread_mutexattr_init(&mattr);    pthread_mutexattr_setpshared(&mattr, PTHREAD_PROCESS_SHARED);    pthread_mutex_init(&buffer->mutex, &mattr);    pthread_condattr_init(&cattr_less);    pthread_condattr_setpshared(&cattr_less, PTHREAD_PROCESS_SHARED);    pthread_cond_init(&buffer->less, &cattr_less);    pthread_condattr_init(&cattr_more);    pthread_condattr_setpshared(&cattr_more, PTHREAD_PROCESS_SHARED);    pthread_cond_init(&buffer->more, &cattr_more);    if (fork() == 0) {        printf("this is child process:");        consume_driver(buffer);    } else {         printf("this is parent process:");        produce_driver(buffer);    }    return 0;}