C++ wininet undefined reference even with -lwininet linker flag

Question

I'm new with WinInet and have following simple C++ code:

void DoIt(std::string& host, std::string& username, std::string& password) {
    HINTERNET hInternet;
    HINTERNET hFtpSession;
    hInternet = InternetOpen(NULL, INTERNET_OPEN_TYPE_DIRECT, NULL, NULL, 0);
    if (hInternet == NULL) {
        std::cout << "Error: " << GetLastError();
    } else {
        hFtpSession = InternetConnect(hInternet, host.c_str(), INTERNET_DEFAULT_FTP_PORT, username.c_str(), password.c_str(), INTERNET_SERVICE_FTP, 0, 0);
        if (hFtpSession == NULL) {
            std::cout << "Error: " << GetLastError();
        } else {
            if (!FtpPutFile(hFtpSession, "C:\\temp\\ftp\\myFile.txt", "/myFile.txt", FTP_TRANSFER_TYPE_BINARY, 0)) {
                std::cout << "Error: " << GetLastError();
            }
        }
    }
}

But compiler's output is:

Info: Configuration "Debug" uses tool-chain "MinGW GCC" that is unsupported on this system, attempting to build anyway.
Info: Internal Builder is used for build
g++ -O0 -g3 -Wall -std=c++11 -o main.o "..\\main.cpp" 
C:\Users\u007\AppData\Local\Temp\ccFEaWlK.o: In function `Z4DoItRSsS_S_':
C:\projects\ftp-test\Debug/../main.cpp:10: undefined reference to `_imp__InternetOpenA@20'
C:\projects\ftp-test\Debug/../main.cpp:14: undefined reference to `_imp__InternetConnectA@32'
C:\projects\ftp-test\Debug/../main.cpp:18: undefined reference to `_imp__FtpPutFileA@20'
collect2.exe: error: ld returned 1 exit status

(I link to wininet.lib library in Eclipse's linker)

(I also tried to add -lwininet option to compiler but it does nothing)

I use following software:

• OS: Windows 10 x64
• IDE: Eclipse Neon 3
• Compiler: MinGW (rubenvb-4.8-stdthread) 4.8.1 20130324 (prerelease)

I saw following links: 1 2 3 but nothing there helps me.

Thanks for any suggestion.

Answer 1

Based on the g++ compile line it's is missing the library to link to (wininet). You need in eclipse to add that library so your program link to it.