#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <pthread.h>
#include <sys/types.h>
#include <sys/stat.h>

#define MAX 50

void* aworking(void* arg);
void* bworking(void* arg);

pthread_mutex_t mutex;

int main(int argc, char const *argv[])
{
    int num = 0;
    pthread_mutex_init(&mutex, NULL);

    pthread_t apid;
    pthread_create(&apid, NULL, aworking, &num);
    
    pthread_t bpid;
    pthread_create(&bpid, NULL, bworking, &num);

    pthread_join(apid, NULL);
    pthread_join(bpid, NULL);
    
    pthread_mutex_destroy(&mutex);

    return 0;
}

void* aworking(void* arg){
    printf("aworking thread id: %lu\n", pthread_self());
    int* num = (int*)arg;
    for (size_t i = 0; i < MAX; i++)
    {
        pthread_mutex_lock(&mutex);
        int cur = *num;
        cur++;
        // 在将寄存器中的数据赋值到内存中的时候，演示10微秒，演示在b线程中每5微秒操作数据时，中间插入a线程操作的数据
        usleep(10);
        *num = cur;
        printf("Thread A, num=%d\n", *num);
        pthread_mutex_unlock(&mutex);
    }

    return NULL;
}

void* bworking(void* arg){
    printf("bworking thread id: %lu\n", pthread_self());
    int* num = (int*)arg;

    for (size_t i = 0; i < MAX; i++)
    {
        pthread_mutex_lock(&mutex);
        int cur = *num;
        cur++;
        *num = cur;
        printf("Thread B, num=%d\n", *num);
        pthread_mutex_unlock(&mutex);
        usleep(5);
    }

    return NULL;
}