arr2sum.c

来自「这是一个很简单的在linux环境下的线程编程例子」· C语言 代码 · 共 54 行

//创建2线程

#include <stdio.h>
#include <unistd.h>
#include <stdlib.h>
#include <pthread.h>
#include "declare.h"

void *parr2sum(void *arg);
extern int array[ARRAY_SIZE];

int flag = 0;
int arr2sum (int count_length)
{
	int res, sum=0;				//线程函数执行的返回值
	struct COUNTPOINT cp[2];
	pthread_t parr1,parr2;	//线程标识符变量
	int result1,result2; //线程执行的返回值
	cp[0].start=0; cp[0].length = count_length/2;
	res = pthread_create(&parr1,NULL,parr2sum,&cp[0]); /*创建线程*/
	if (res!=0) {
		perror("Create Thread failed");//创建失败
		exit(EXIT_FAILURE);
	} 

	cp[1].start=cp[0].length; cp[1].length = count_length-cp[0].length;
	res = pthread_create(&parr2,NULL,parr2sum,&cp[1]); /*创建线程*/
	if (res!=0) {
		perror("Create Thread failed");//创建失败
		exit(EXIT_FAILURE);
	}
	res = pthread_join(parr1,(void**)&result1);     sum += result1;//归并相加
	res = pthread_join(parr2,(void**)&result2);     sum += result2;
	return sum;
}

//2线程数组数之和
void *parr2sum(void *arg) 
{
	int i,sum=0;
	int* pa;
	struct COUNTPOINT cp;
	cp = *(struct COUNTPOINT*)arg;
	pa = array+cp.start;
	for (i=0; i<cp.length; i++)
	{
		sum += pa[i]; //数组数之和
	}

	pthread_exit((void*)sum);//线程退出
}