Cmake Openssl And Mingw On Windows Linker errors

If you found this you are probably having issues linking OpenSSL to MinGW-w64 using CMake (or CLion) on Windows. In this post I will give a quick overview on how to get this to work on a clean Windows machine…

The distribution I used to get it to work is Win64OpenSSL-1_2_2k.exe. The issue was that there are no MinGW-compatible link libaries. To solve this you can use my genlib tool to generate them:

cd c:\OpenSSL-Win64
set PATH=%PATH%;c:\genlib

genlib ssleay32.dll
genlib libeay32.dll

copy *.a lib\

The CMakeLists.txt looks like this:

# Project configuration
cmake_minimum_required(VERSION 2.7)
project(OpenSSLTest)

# Use C++11
set(CMAKE_CXX_STANDARD 11)

# Project source files
set(SOURCE_FILES main.cpp)
add_executable(OpenSSLTest ${SOURCE_FILES})

# OpenSSL (find, include, link) 
find_package(OpenSSL REQUIRED)
include_directories(${OPENSSL_INCLUDE_DIR})
target_link_libraries(${PROJECT_NAME} ${OPENSSL_LIBRARIES})

And some simple test code:

#include <iostream>
#include <openssl/ssl.h>

int main() {
    std::cout << "SSLeay Version: " << SSLeay_version(SSLEAY_VERSION) << std::endl;
    SSL_library_init();
    auto ctx = SSL_CTX_new(SSLv23_client_method());
    if (ctx) {
        auto ssl = SSL_new(ctx);
        if (ssl) {
            std::cout << "SSL Version: " << SSL_get_version(ssl) << std::endl;
            SSL_free(ssl);
        } else {
            std::cout << "SSL_new failed..." << std::endl;
        }
        SSL_CTX_free(ctx);
    } else {
        std::cout << "SSL_CTX_new failed..." << std::endl;
    }
}

If everything is configured correctly this should print:

SSLeay Version: OpenSSL 1.0.2k  26 Jan 2017
SSL Version: TLSv1.2

If you cannot be bothered to run genlib yourself, you can find a copy the required files here and get started immediately.

Hope this helped,

Duncan