为什么调用了 strcat_s函数还是无法将 两个字符串连接起来
#include<stdio.h>
#include<string.h>
int main()
{
char str1[30];
char str2[30];
printf("input purposive string:\n");
fgets(str1, 30, stdin);
printf("input original string:\n");
fgets(str2, 30, stdin);
printf("output purposive string:\n");
fputs(str1, stdout);
printf("output original string:\n");
fputs(str2, stdout);
strcat_s(str1,30, str2);
printf("strcat function called for string connection:\n");
printf("the purposive string after string connection:\n");
fputs(str1,stdout);
return 0;
}