pthread_mutex_lock.c

pthread soure code

#include <stdio.h> 
#include <pthread.h> 

void reader_function ( void );
void writer_function ( void );

char buffer;
int buffer_has_item=0;
pthread_mutex_t mutex;
struct timespec delay;

int main ( void ){
pthread_t reader;
/* 定义延迟时间*/
delay.tv_sec = 2;
delay.tv_nec = 0;
/* 用默认属性初始化一个互斥锁对象*/
pthread_mutex_init (&mutex,NULL);
pthread_create(&reader, pthread_attr_default, (void *)&reader_function), NULL);
writer_function( );
return 0;
}

void writer_function (void){
while(1){
/* 锁定互斥锁*/
pthread_mutex_lock (&mutex);
if (buffer_has_item==0){
buffer=make_new_item( );
buffer_has_item=1;
}
/* 打开互斥锁*/
pthread_mutex_unlock(&mutex);
pthread_delay_np(&delay);
}
}

void reader_function(void){
while(1){
pthread_mutex_lock(&mutex);
if(buffer_has_item==1){
consume_item(buffer);
buffer_has_item=0;
}
pthread_mutex_unlock(&mutex);
pthread_delay_np(&delay);
}
}