3个线程使用的都是同一个info
代码 Info_t *info = (Info_t *)malloc(sizeof(Info_t))只创建了一个info
pthread_create(&threads[i],NULL,calMatrix,(void *)info)三个线程使用的是同一个
我把你的代码改了下:
#include <stdio.h>#include <stdlib.h>
#include <pthread.h>
int mtc[3] = { 0 } // result matrix
typedef struct
{
int prank
int *mta
int *mtb
}Info_t
void* calMatrix(void* arg)
{
int i
Info_t *info = (Info_t *)arg
int prank = info->prank
fprintf(stdout,"calMatrix : prank is %d\n",prank)
for(i = 0 i < 3 i++)
mtc[prank] += info->mta[i] * info->mtb[i]
return NULL
}
int main(int argc,char **argv)
{
int i,j,k = 0
int mta[3][3]
int mtb[3] = { 1 }
Info_t *info = (Info_t *)malloc(sizeof(Info_t)*3)
for(i = 0 i < 3 i++)
for(j = 0 j < 3 j++)
mta[i][j] = k++
/* 3 threads */
pthread_t *threads = (pthread_t *)malloc(sizeof(pthread_t)*3)
fprintf(stdout,"\n")fflush(stdout)
for(i = 0 i < 3 i++)
{
info[i].prank = i
info[i].mta = mta[i]
info[i].mtb = mtb
pthread_create(&threads[i],NULL,calMatrix,(void *)(&info[i]))
}
for(i = 0 i < 3 i++)
pthread_join(threads[i],NULL)
fprintf(stdout,"\n==== the matrix result ====\n\n")
fflush(stdout)
for(i = 0 i < 3 i++)
{
fprintf(stdout,"mtc[%d] = %d\n",i,mtc[i])
fflush(stdout)
}
return 0
}
矩阵的计算我忘记了,你运行看看结果对不对
你编译的时候有加多线程连接选项吗? 要加上 -lpthread 或者 -pthread (尽量选后者)例如 gcc -pthread -o test main.cpp
另外你的线程创建的不对,函数指针不能强转类型(这里也不用转)
pthread_create(&producter_t,NULL,(void*)producter_f,NULL)
pthread_create(&consumer_t,NULL,(void*)consumer_f,NULL)
应该是
pthread_create(&producter_t,NULL,producter_f,NULL)
pthread_create(&consumer_t,NULL,consumer_f,NULL)
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