Errno and PERROR

Linux Error code and its meaning

#include <iostream>
#include <fstream>
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <syslog.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>
using namespace std;
int bindPort(int nPort)
{
	struct sockaddr_in servaddr;
	int sockfd, ret;
	sockfd = socket(AF_INET, SOCK_STREAM, 0);
	if (-1 == sockfd)
		return -1;

	bzero(&servaddr, sizeof(servaddr));
	servaddr.sin_family = AF_INET;
	servaddr.sin_port = htons(nPort);
	inet_pton(AF_INET, "0.0.0.0", &servaddr.sin_addr);

	ret = bind(sockfd, (struct sockaddr *)&servaddr, sizeof(struct sockaddr));
  if(0!=ret)
  {

    perror("Unable to bind socket");
    cout << "errno = " << errno <<  endl;
    char*errReason = strerror(errno);
    cout << "errReason = " << errReason << endl;
  }
	close(sockfd);
	return ret;
}

bool CheckPortInUse(int nPort)
{
	struct sockaddr_in servaddr;
  bool ifInUse = false;
	int sockfd, ret;
	sockfd = socket(AF_INET, SOCK_STREAM, 0);
	if (-1 == sockfd)
		return -1;

	bzero(&servaddr, sizeof(servaddr));
	servaddr.sin_family = AF_INET;
	servaddr.sin_port = htons(nPort);
	inet_pton(AF_INET, "0.0.0.0", &servaddr.sin_addr);

	ret = bind(sockfd, (struct sockaddr *)&servaddr, sizeof(struct sockaddr));
  if(0!=ret && errno == EADDRINUSE)
  {
     ifInUse = true;
  }
	close(sockfd);
	return ifInUse;
}

int main()
{
   //int ret = CheckPortIsAvailable(6379);
   //cout << "ret = " << ret << endl;
   bool ifInUse = CheckPortInUse(6379);
   if(true == ifInUse)
   {
     cout << " The port is occupied " << endl;
   }
   else 
   {
     cout << " The port is not occupied " << endl;
   }
}