代码

#include <stdio.h>

#include <stdlib.h>

#include <pthread.h>

#define N 4

int A[N][N],sum[N];

void *func(void arg)
{
int j,row ;
pthread_t tid = pthread_self();
row = (int)arg;
printf("Thread %d [%lu] computes sum of row %d\n",row,tid,row);
for(j=0;j<N; j++)
sum[row] += A[row][j];
printf("Thread %d [%lu] done:sum [%d] =%d\n",row,tid,row,sum[row]);
pthread_exit ((void)0);
}
int main(int argc, char *argv[])
{
pthread_t thread[N];
int i,j,r,total = 0;
void status;
printf("Main: initialize A matrix\n");
for(i=0; i<N;i++){
sum[i] = 0;
for(j=0;j<N;j++){
A[i][j]=iN+j+1;
printf("%4d ",A[i][j]);
}
printf( "\n" );
}
printf ("Main: create %d threads\n",N);
for(i=0;i<N;i++) {
pthread_create(&thread[i],NULL,func,(void *)i);
}
printf("Main: try to join with thread\n");
for(i=0; i<N; i++) {
pthread_join(thread[i],&status);
printf("Main: joined with %d [%lu]: status=%d\n",i,thread[i],
(int)status);
}
printf("Main: compute and print total sum:");
for(i=0;i<N;i++)
total += sum[i];
printf ("tatal = %d\n",total );
pthread_exit(NULL);
}