pthread_cond_signal(&empty);//这句不执行，下句pthread_mutex_unlock(&lock);也跟着不执行？

C/C++ code

#include <stdio.h>#include <pthread.h>/*仓库*/char stack[6];int size=0;/*互斥量，用来保护临界资源*/pthread_mutex_t lock=PTHREAD_MUTEX_INITIALIZER;/*条件变量,相当于线程的等待队列*/pthread_cond_t full=PTHREAD_COND_INITIALIZER;pthread_cond_t empty=PTHREAD_COND_INITIALIZER;/*打印仓库*/void print(){    int i;    for(i=0; i<size; i++){        printf("%c ", stack[i]);    }    printf("\n");}/*生产者*/void* producer(void* p){    char c;    for(c='A'; c<='Z'; c++){        pthread_mutex_lock(&lock);        while(size==6){            pthread_cond_wait(&full, &lock);        }        stack[size] = c;        printf("%c PUT\n", c);        size++;        print();        pthread_cond_signal(&empty);        pthread_mutex_unlock(&lock);        usleep(200*1000);    }}/*消费者*/void* customer(void* p){    int i;    for(i=0; i<52; i++){        pthread_mutex_lock(&lock);        while(size==0)            pthread_cond_wait(&empty, &lock);//&lock是什么意思？        size--;        printf("%c POP\n", stack[size]);        print();        pthread_cond_broadcast(&full);        pthread_mutex_unlock(&lock);        usleep(400*1000);    }}int main(){    pthread_t pid1, pid2, cid;    pthread_create(&pid1, 0, producer, 0);    pthread_create(&pid2, 0, producer, 0);    pthread_create(&cid, 0, customer, 0);    pthread_join(pid1, 0);    pthread_join(pid2, 0);    pthread_join(cid, 0);}

C/C++ code

#include <stdio.h>#include <stdlib.h>#include <pthread.h>static int num_products = 0;static int num_room = 10;static int num_to_make = 50;static pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;static pthread_cond_t cond = PTHREAD_COND_INITIALIZER;static void* factory(void *arg) {    int to_make = 0;    for (; to_make != num_to_make; ++ to_make) {        pthread_mutex_lock(&mutex);        while (num_products == num_room) {            pthread_cond_wait(&cond, &mutex);        }        ++ num_products;        fprintf(stderr, "factory makes %dth product, storage %d\n", to_make, num_products);        pthread_cond_signal(&cond);        pthread_mutex_unlock(&mutex);    }    return NULL;}static void* customer(void *arg) {    int to_use = 0;    for (; to_use != num_to_make; ++ to_use) {        pthread_mutex_lock(&mutex);        while (num_products == 0) {            pthread_cond_wait(&cond, &mutex);        }        -- num_products;        fprintf(stderr, "customer gets %dth product, storage %d\n", to_use, num_products);        pthread_cond_signal(&cond);        pthread_mutex_unlock(&mutex);    }    return NULL;}int main(int argc, char* const argv[]) {    pthread_t fac, cus;    pthread_create(&fac, NULL, factory, NULL);    pthread_create(&cus, NULL, customer, NULL);        void *ret;    pthread_join(fac, &ret);    pthread_join(cus, &ret);    return 0;}
[解决办法]
C/C++ code
#include <stdio.h>#include <stdlib.h>#include <pthread.h>/* *    1:n or m:n *    两个条件变量的用法. * */static pthread_mutex_t full_mutex = PTHREAD_MUTEX_INITIALIZER;static pthread_cond_t full_cond = PTHREAD_COND_INITIALIZER;static pthread_mutex_t empty_mutex = PTHREAD_MUTEX_INITIALIZER;static pthread_cond_t empty_cond = PTHREAD_COND_INITIALIZER;static int num_space = 10;static int num_full = 0;  //customer可取个数static int num_empty = 10; //factory可放个数static int num_to_make = 50;static void* factory(void *arg) {    int ndx;     for (ndx = 0; ndx != num_to_make; ++ ndx) {        pthread_mutex_lock(&empty_mutex);        while (num_empty == 0) {            pthread_cond_wait(&empty_cond, &empty_mutex);        }        -- num_empty;        pthread_mutex_unlock(&empty_mutex);        pthread_mutex_lock(&full_mutex);        ++ num_full;        fprintf(stderr, "factory %dth storage %d\n", ndx, num_full);        pthread_cond_signal(&full_cond);        pthread_mutex_unlock(&full_mutex);    }    return NULL;}static void* customer(void *arg) {    int ndx;    for (ndx = 0; ndx != num_to_make; ++ ndx) {        pthread_mutex_lock(&full_mutex);        while (num_full == 0) {            pthread_cond_wait(&full_cond, &full_mutex);        }        -- num_full;        pthread_mutex_unlock(&full_mutex);                pthread_mutex_lock(&empty_mutex);        ++ num_empty;        fprintf(stderr, "customer %dth storage %d\n", ndx, 10 - num_empty);        pthread_cond_signal(&empty_cond);        pthread_mutex_unlock(&empty_mutex);    }    return NULL;}int main(int argc, char* const argv[]) {    pthread_t fac, cus;    void *ret;    /* 不模拟1:n, m:n了, 情景不适合 */    pthread_create(&fac, NULL, factory, NULL);    pthread_create(&cus, NULL, customer, NULL);    pthread_join(fac, &ret);    pthread_join(cus, &ret);    return 0;}