我想从0进程到1-6进程发送消息(问候语(,每次在消息后面加上数字I(G_str(,但结果显示
processor 1 received string: from processor 0
processor 2 received string: from processor 0
...
我不知道它没有显示我想发送的信息
#include <stdio.h>
#include <string.h>
#include <mpi.h>
int main(int argc, char *argv[])
{
int PID, P;
char greeting [] = "hello";
char replying [] ="nice to see you";
char G_str [10];
char R_str [10];
MPI_Init(&argc, &argv);
MPI_Comm_size(MPI_COMM_WORLD, &P);
MPI_Comm_rank(MPI_COMM_WORLD, &PID);
int len_g = strlen(greeting);
int len_r = strlen(replying);
int len_G = strlen(G_str);
//send and receive//
if (PID == 0){
for (int i = 1; i <= 6; i++)
{
sprintf(G_str, "%s%d", greeting,i);
MPI_Send(&G_str, len_G, MPI_CHAR, i, 77, MPI_COMM_WORLD);
}
}
else{
MPI_Recv(&G_str, len_G, MPI_CHAR, 0, 77, MPI_COMM_WORLD, MPI_STATUS_IGNORE);
printf("processor %d received string %s from processor 0 n", PID, G_str);
}
MPI_Finalize();
}
我想问题出在G_str的长度上,但如何纠正它?
char G_str [10];
G_str
未初始化。您只需使用该语句声明char
数组G_str
,但不初始化字符串。
因此:
int len_G = strlen(G_str);
您将得到Undefined Behavior,因为strlen
搜索以NUL结尾的字符串的