unix高级环境编程---11章 线程 学习

零散知识。

1.线程id--- 进程id的类型是pid_t， 线程id的类型是pthread_t;

比较两个线程id：

#include

int pthread_equal ( pthread_t tid1, pthread_t tid2 );

获得自身的线程id：

pthread_t pthread_self(void)

2.线程创建

int pthread_create( pthread_t *restrict tidp, const pthread_attr_t *restrict attr,

void *(*start_rtn)(void *), void *restrict arg );

接下来是打印线程id的例子：

#include
#include
#include
#include
#include
#include
pthread_t ntid;

void printids(const char *s){
pid_t pid;
pthread_t tid;
pid = getpid();
tid = pthread_self();
printf("%s pid %u tid %u (0x%x)\n",s, (unsigned int)pid,
(unsigned int)tid, (unsigned int) tid);

}
void *thr_fn(void *arg){
printids("new thread: ");
return ((void*)0);

}

int main(){
int err = 0;
err = pthread_create(&ntid, NULL, thr_fn, NULL);
//err = pthread_create(&ntid, NULL, thr_fn, NULL);
if(err!=0){
printf("%s\n", strerror(err) );

}
printids("main thread:");
sleep(1);
exit(0);
}

使用ubuntu，eclipse编译，提示找不到pthread_create. 头文件是定义了，但是没有连接线程库。 需要设置eclipse。 选择工程--属性--c、c++build--settings---gcc c linker---libraries， 添加库 pthread。 再次编译运行。ok。

main thread: pid 2164 tid 3079145152 (0xb78806c0)
new thread: pid 2164 tid 3079142256 (0xb787fb70)

3、线程终止

void *thr_fn1(void *arg){
printf("thread 1 returning\n");
return ((void* )1);

}

void *thr_fn2(void *arg){
printf("thread 2 exiting\n");
pthread_exit((void *)1);

}

int main(){
int err;
pthread_t tid1, tid2;
void *tret;
err = pthread_create(&tid1, NULL, thr_fn1, NULL);
if( err != 0){
printf("can't create thread 1:%s\n", strerror(err));
}
err = pthread_create(&tid2, NULL, thr_fn2, NULL);
if( err!=0){
printf("can't create thread 2:%s\n", strerror(err));
}
err = pthread_join(tid1, &tret);
if(err!=0){
printf("can't join with thread 1:%s\n", strerror(err));

}
printf(" thread 1 exit code %d\n", (int)tret);
err = pthread_join(tid2, &tret);
if(err!=0){
printf("can't join eith thread 2:%s\n", strerror(err));
}
printf("thread 2 exit code %d\n", (int)tret);
exit(0);
}