C語言中pthread_create函數(shù)實現(xiàn)向線程函數(shù)傳遞參數(shù)

更新時間：2023年05月30日 16:11:04 作者：焱齒

本文主要介紹了C語言中pthread_create函數(shù)實現(xiàn)向線程函數(shù)傳遞參數(shù)，文中通過示例代碼介紹的非常詳細，對大家的學習或者工作具有一定的參考學習價值，需要的朋友們下面隨著小編來一起學習學習吧

一、pthread_create函數(shù)：

1、簡介：pthread_create是UNIX環(huán)境創(chuàng)建線程的函數(shù)

2、頭文件：#include <pthread.h>

3、函數(shù)聲明：

int pthread_create(pthread_t* restrict tidp,const pthread_attr_t* restrict_attr,void* (*start_rtn)(void*),void *restrict arg);

4、輸入參數(shù)：（以下做簡介，具體參見實例一目了然）

（1）tidp：事先創(chuàng)建好的pthread_t類型的參數(shù)。成功時tidp指向的內存單元被設置為新創(chuàng)建線程的線程ID。

（2）attr：用于定制各種不同的線程屬性。APUE的12.3節(jié)討論了線程屬性。通常直接設為NULL。

（3）start_rtn：新創(chuàng)建線程從此函數(shù)開始運行。無參數(shù)是arg設為NULL即可。

（4）arg：start_rtn函數(shù)的參數(shù)。無參數(shù)時設為NULL即可。有參數(shù)時輸入參數(shù)的地址。當多于一個參數(shù)時應當使用結構體傳入。（以下舉例）

5、返回值：成功返回0，否則返回錯誤碼。

6、說明。

傳遞參數(shù)的時候傳地址： pthread_create(&ntid, NULL, thr_fn, &param1);

線程函數(shù)的第一句通常是獲取傳入參數(shù)：Param tmp = *(Param *)arg;

舉例如下：

二、不向線程函數(shù)傳遞參數(shù)：

#include "apue.h"
#include <pthread.h>
#include "apueerror.h"
#include <iostream>
#include <string>
using namespace std;
pthread_t ntid;
void printids(const char *s){
	pid_t		pid;
	pthread_t	tid;
	pid = getpid();
	tid = pthread_self();
	printf("%s pid %lu tid %lu (0x%lx)\n", s, (unsigned long)pid,
	  (unsigned long)tid, (unsigned long)tid);
}
void *thr_fn(void *arg){
    cout << "----enter sub thread--------" << endl;
	printids("new thread: ");
	cout << "Change to C++ code!!" << endl;
    cout << "----exit from sub thread----" << endl;
	return((void *)0);
}
int main(void){
	int		err;
    //第四個參數(shù)為NULL，說明沒有向線程函數(shù)傳參數(shù)。
	err = pthread_create(&ntid, NULL, thr_fn, NULL);
	if (err != 0)
		err_exit(err, "can't create thread");
	printids("main thread:");
	sleep(1);
	exit(0);
}

三、向線程函數(shù)傳遞一個參數(shù)：

#include "apue.h"
#include <pthread.h>
#include "apueerror.h"
#include <iostream>
#include <string>
using namespace std;
pthread_t ntid;
void printids(const char *s){
	pid_t		pid;
	pthread_t	tid;
	pid = getpid();
	tid = pthread_self();
	printf("%s pid %lu tid %lu (0x%lx)\n", s, (unsigned long)pid,
	  (unsigned long)tid, (unsigned long)tid);
}
struct Param {
	int a;
	int b;
	int c;
};
void *thr_fn( void *arg ) {
    cout << "----enter sub thread--------" << endl;
	int tmp = *(int *)arg;
	cout << "tmp=" << tmp << endl;
	printids("new thread: ");
	cout << "Change to C++ code!!" << endl;
    cout << "----exit from sub thread----" << endl;
	return((void *)0);
}
int main(void){
	int		err;
	int num = 123;
    //向線程函數(shù)傳入一個參數(shù)。
	err = pthread_create(&ntid, NULL, thr_fn, &num);
	if (err != 0)
		err_exit(err, "can't create thread");
	printids("main thread:");
	sleep(1);
	exit(0);
}

四、向線程函數(shù)傳遞兩個或以上的參數(shù)：

#include "apue.h"
#include <pthread.h>
#include "apueerror.h"
#include <iostream>
#include <string>
using namespace std;
pthread_t ntid;
void printids(const char *s){
	pid_t		pid;
	pthread_t	tid;
	pid = getpid();
	tid = pthread_self();
	printf("%s pid %lu tid %lu (0x%lx)\n", s, (unsigned long)pid,
	  (unsigned long)tid, (unsigned long)tid);
}
struct Param {
	int a;
	int b;
	int c;
};
void *thr_fn(void *arg) {
    cout << "----enter sub thread--------" << endl;
	Param tmp = *(Param *)arg;
	cout << "tmp.a=" << tmp.a << endl;
	cout << "tmp.b=" << tmp.b << endl;
	cout << "tmp.c=" << tmp.c << endl;
	printids("new thread: ");
	cout << "Change to C++ code!!" << endl;
    cout << "----exit from sub thread----" << endl;
	return((void *)0);
}
int main(void){
	int		err;
	int num = 123;
	Param param1;
	param1.a = 11;
	param1.b = 22;
	param1.c = 33;
    //通過結構體向線程函數(shù)傳入多個參數(shù)
	err = pthread_create(&ntid, NULL, thr_fn, &param1);
	if (err != 0)
		err_exit(err, "can't create thread");
	printids("main thread:");
	sleep(1);
	exit(0);
}

執(zhí)行效果如下: