Connect method in winsock2 does not seem to work - c++

Question

#define PORT 3000
int sock()
{
int valread;
struct sockaddr_in serv_addr;
const char* hello = "Hello from client";
char buffer[1024] = { 0 };
SOCKET sock = socket(AF_INET, SOCK_STREAM, 0);
if (sock < 0)
{
printf("\n Socket creation error \n");
return -1;
}
serv_addr.sin_family = AF_INET;
serv_addr.sin_port = htons(PORT);
// Convert IPv4 and IPv6 addresses from text to binary form
if (inet_pton(AF_INET, "127.0.0.1", &serv_addr.sin_addr) <= 0)
{
printf("\nInvalid address/ Address not supported \n");
return -1;
}
if (connect(sock, (struct sockaddr*)&serv_addr, sizeof(serv_addr)) < 0)
{
printf("\nConnection Failed \n");
return -1;
}
send(sock, hello, strlen(hello), 0);
printf("Hello message sent\n");
return 0;
}
I have this code for the sockets, to be sent at localhost:3000 address. But they are not sent, and Connection failed error pops up. I have node.js server listener socket open at that port.

Answer 1

On Windows only 1, you must call WSAStartup() to initialize the Winsock library before using any other socket functions, like connect(). See Initializing Winsock. And you should call WSACleanup() when you are done using Winsock.
1: On non-Windows platforms, there are no equivalent startup/cleanup functions that need to be called when using sockets.
Try something more like this:
#include <winsock2.h>
#include <windows.h>
#include <stdio.h>
#define PORT 3000
int main()
{
WSADATA wsa;
int iResult = WSAStartup(MAKEWORD(2,0), &wsa);
if (iResult != 0)
{
printf("WSAStartup failed: %d\n", iResult);
return INVALID_SOCKET;
}
printf("Winsock initialized\n");
struct sockaddr_in serv_addr;
ZeroMemory(&serv_addr, sizeof(serv_addr));
serv_addr.sin_family = AF_INET;
serv_addr.sin_port = htons(PORT);
// Convert IPv4 and IPv6 addresses from text to binary form
if (inet_pton(AF_INET, "127.0.0.1", &serv_addr.sin_addr) <= 0)
{
printf("Invalid address/ Address not supported \n");
WSACleanup();
return -1;
}
SOCKET sock = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
if (sock == INVALID_SOCKET)
{
printf("Socket creation failed: %d\n", WSAGetLastError());
WSACleanup();
return -1;
}
if (connect(sock, (struct sockaddr*)&serv_addr, sizeof(serv_addr)) == SOCKET_ERROR)
{
printf("Connection failed: %d\n", WSAGetLastError());
closesocket(sock);
WSACleanup();
return -1;
}
printf("Connection successful\n");
const char* hello = "Hello from client";
if (send(sock, hello, strlen(hello), 0) == SOCKET_ERROR)
{
printf("Send failed: %d\n", WSAGetLastError());
closesocket(sock);
WSACleanup();
return -1;
}
printf("Hello message sent\n");
closesocket(sock);
WSACleanup();
return 0;
}
That said, you really should be using getaddrinfo() instead of inet_pton(), especially if you want to support both IPv4 and IPv6, eg:
#include <winsock2.h>
#include <ws2tcpip.h>
#include <windows.h>
#include <stdio.h>
#define PORT "3000"
int main()
{
WSADATA wsa;
int iResult = WSAStartup(MAKEWORD(2,0), &wsa);
if (iResult != 0)
{
printf("WSAStartup failed: %d\n", iResult);
return INVALID_SOCKET;
}
printf("Winsock initialized\n");
struct addrinfo hints, *addrs;
ZeroMemory(&hints, sizeof(hints));
hints.ai_family = AF_UNSPEC;
hints.ai_socktype = SOCK_STREAM;
hints.ai_protocol = IPPROTO_TCP;
// Convert IPv4 and IPv6 addresses from text to binary form
iResult = getaddrinfo("127.0.0.1", PORT, &hints, &addrs);
if (iResult != 0)
{
printf("Get Address Info failed: (%d) %s\n", iResult, gai_strerror(iResult));
WSACleanup();
return -1;
}
SOCKET sock = INVALID_SOCKET;
for(struct addrinfo *addr = addrs; addr != NULL; addr = addr->ai_next)
{
sock = socket(addr->ai_family, addr->ai_socktype, addr->ai_protocol);
if (sock != INVALID_SOCKET)
{
if (connect(sock, addr->ai_addr, addr->ai_addrlen) != SOCKET_ERROR)
break;
closesocket(sock);
sock = INVALID_SOCKET;
}
}
if (sock == INVALID_SOCKET)
{
printf("Socket creation failed/Connection failed\n");
WSACleanup();
return -1;
}
printf("Connection successful\n");
const char* hello = "Hello from client";
if (send(sock, hello, strlen(hello), 0) == SOCKET_ERROR)
{
printf("Send failed: %d\n", WSAGetLastError());
closesocket(sock);
WSACleanup();
return -1;
}
printf("Hello message sent\n");
closesocket(sock);
WSACleanup();
return 0;
}