Why does the program not execute print statements in main?

Question

#include <sys/socket.h>
#include<stdio.h>
#include <netinet/in.h>
#include<string.h>
int init_socket(int *fd, int port){
    struct sockaddr_in serv_addr, cli_addr;
    *fd = socket(AF_INET, SOCK_STREAM, 0);
    memset((char *) &serv_addr, 0, sizeof(serv_addr));
    serv_addr.sin_family = AF_INET;
    serv_addr.sin_addr.s_addr = INADDR_ANY;
    serv_addr.sin_port = htons(port);
    bind(*fd, (struct sockaddr *) &serv_addr,
                      sizeof(serv_addr))
    listen(*fd,1); //Change as per requirement
}

int connect_server()
{
    int fd, j, result;
    fd_set readset;
    init_socket(&fd,6001);
        while(1){
          FD_ZERO(&readset);
          FD_SET(fd, &readset);
          select(3, &readset, NULL, NULL, NULL);
          }
}

int main(){
printf("Main Start");
connect_server();
printf("Main End");
}

I am trying to execute this code but none of the printf() is displayed. When the select() is removed from the code the printf() works correctly. Why does this happen?

Answer 1

Try again by appending a newline at the end of the string:

int main(){
printf("Main Start\n");
connect_server();
printf("Main End\n");
}

Reason: stdout is line buffered, and you'll need to give it a newline to flush the output.

Or explicitly flush it by fflush(stdout);.