[C++] Detect Hostname & Username. (Check if they are same) LINUX

user_hostname.cpp

#include <iostream>
#include <unistd.h>
#include <limits.h>
#include <string.h>

int main()
{
    char hostname[HOST_NAME_MAX];
    char loginName[LOGIN_NAME_MAX];
    
    gethostname(hostname, HOST_NAME_MAX);
    getlogin_r(loginName, LOGIN_NAME_MAX);
    
    if(hostname == NULL)
    {
        std::cout << "Unable to get Hostname!" << std::endl;
    } else {
        std::cout << "[HOSTNAME]: " << hostname << std::endl; 
    }
    
    std::cout << "Getting Logged User." << std::endl;
    
    if(loginName == NULL)
    {
        std::cout << "Unable to get Logged User Name" << std::endl;
    } else {
        std::cout << "[USERNAME]: " << loginName << std::endl;
    }
    
    
    if(strcmp(loginName, hostname) == 0){
        std::cout << "Username/Hostname same." << std::endl;
    } else {
        std::cout << "[OK]" << std::endl;
    }
    
    return 0; 
}