cwinapiwinsock2

where is WSASocket defined?

I am trying to dynamically link winsock functions starting with WSASocket, the following code compile just fine

#include <stdio.h>
#include <winsock2.h>
#include <windows.h>

typedef SOCKET (WINAPI * pWSASocket)(int, int, int, LPWSAPROTOCOL_INFOA, GROUP, DWORD);

int main()
{
        HMODULE hmod = LoadLibrary("ws2_32.dll");
        if (hmod == NULL)
        {
                printf("Failed to load ws2_32.dll\n");
                exit(EXIT_FAILURE);
        }

        pWSASocket WSASocket = (pWSASocket)GetProcAddress(hmod, "WSASocket");
        if (WSASocket == NULL)
        {
                printf("Failed to find function WSASocket\n");
                exit(EXIT_FAILURE);
        }
        return 0;
}

but when running the binary I get the error Failed to find function WSASocket

According the WINAPI docs WSASocket should be in Ws2_32.dll but the GetProcAddress returns a NULL value

Solution

  • WSASocket is a preprocessor symbol declared in WinSock2.h, not the name of an exported symbol. The symbols exported by ws2_32.dll are named WSASocketA or WSASocketW.

    Since your function pointer declaration uses LPWSAPROTOCOL_INFOA, you'll probably want to resolve WSASocketA. If you were to use load-time dynamic linking instead, this would produce a deprecation warning.

    If that is something you care about, link to the WSASocketW symbol instead and use LPWSAPROTOCOL_INFOW in the function pointer declaration.