Cross compile Static Library from Linux for windows

When developing software, there is a high chance that software might be used in various operating systems. Therefore, it is important to build software in a cross-platform manner to ensure compatibility with multiple operating systems. In this article, we will focus on cross-compiling static libraries from Linux for Windows.

What is a Static Library?

A static library is a file that contains pre-compiled code that can be linked with an executable program to create a single, self-contained executable. The code in a static library is linked directly into the executable, which makes it faster and more efficient than dynamic libraries.

What is Cross-Compiling?

Cross-compiling is the process of building software on one platform that is intended to run on a different platform. For example, building a Windows application on a Linux machine.

Why Cross-Compile?

Cross-compiling has several benefits, such as

• Increased productivity Cross-compiling saves time, allowing developers to build for multiple platforms without having to switch between different machines.

• Improved portability Cross-compiling ensures that software is compatible with multiple platforms.

• Reduced development costs Cross-compiling eliminates the need for multiple machines and operating systems, reducing hardware and software costs.

• Easier testing Cross-compiling enables developers to test their software on multiple platforms, without the need for physical hardware.

Cross-Compiling Process Overview

Step-by-Step Implementation

Step 1 Install Required Cross-Compiler

The first step is to install a cross-compiler that will allow us to compile our code for Windows on a Linux machine. For this tutorial, we will use Mingw-w64 cross-compiler.

To install Mingw-w64 cross-compiler on Ubuntu, run the following command

sudo apt-get install mingw-w64

Step 2 Create Source Code

Create a simple static library with a "hello world" function. Create a file called hello.c

#include <stdio.h>

void hello() {
   printf("Hello, world!<br>");
}

Step 3 Compile to Object File

Compile the source code into an object file using the cross-compiler

x86_64-w64-mingw32-gcc -c hello.c -o hello.o

This command compiles hello.c into an object file called hello.o compatible with Windows.

Step 4 Create Static Library

Create the static library from the object file using the archiver tool

x86_64-w64-mingw32-ar rcs libhello.a hello.o

This creates a static library file libhello.a from the object file hello.o.

Step 5 Create Test Application

Create a Windows application to test the static library. Create main.c

#include <windows.h>
extern void hello();

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow) {
   hello();
   return 0;
}

Step 6 Compile Windows Application

Compile the test application and link it with the static library

x86_64-w64-mingw32-gcc main.c -o main.exe -L. -lhello -mwindows

The -L. option tells the compiler to look for libraries in the current directory, and -lhello links with the libhello.a static library.

Key Considerations

Common Cross-Compiler Tools

Conclusion

Cross-compiling static libraries from Linux for Windows using Mingw-w64 is an efficient way to develop cross-platform software. This approach saves development time, reduces costs, and ensures compatibility across multiple operating systems without requiring separate development environments for each target platform.