How to build windowless Lua for Windows

how_to_build_wlua_for_windows.md

What is "windowless Lua"?

Windowless Lua does not create a console window.
It runs invisible for user.

Please note that "windowless" means "doesn't have stdin, stdout and stderr".
You will not be able to see error message.
io.read(), io.write() and print() in your Lua script will not work.
But in some situations invisible Lua is just what you need very much.
For example, to avoid a GUI application (especially a game) to lose input focus when some background Lua script is started.

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How to build 64-bit windowless Lua 5.4 binaries for Windows

1. Download the latest Lua sources

   • Create temporary folder for Lua sources.
     I assume you would use C:\Temp\ folder.

   • Visit Lua FTP webpage and download the latest Lua source archive, currently it is lua-5.4.3.tar.gz

   • Use suitable software (7-Zip, WinRar, WinZip or TotalCommander) to unpack the archive.
     Please note that with 7-Zip you have to unpack it twice: lua-5.4.3.tar.gz -> lua-5.4.3.tar -> lua-5.4.3\

   • Move unpacked Lua sources to C:\Temp\lua-5.4.3\

2. Modify Lua sources

   • Open folder C:\Temp\lua-5.4.3\src\

   • Find the file lua.c, right-click it and select "Edit".
     Notepad will open.
     Text might look weird because Notepad does not recognize UNIX-style newline characters.
     Please ignore this problem.

   • Scroll down to the end of the file and add the following 2 lines after the last line:
     int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nShowCmd)
{ return main(__argc, __argv); }

   • Save the file and close Notepad.

3. Build Lua binaries using MinGW64

   • Download and install MSYS2.
     It is recommended to install MSYS2 in the default destination folder C:\msys64\,
     but you may choose another path consisting of English letters without spaces.

   • After installation is complete, a MSYS2 console window will open.
     Execute the following command in this MSYS2 console window:
     pacman -S mingw-w64-x86_64-gcc mingw-w64-x86_64-make
     When asked Proceed with installation? [Y/n], answer Y and press Enter.

   • Close this MSYS2 console window and open a new one by clicking the MSYS2 MinGW 64-bit menu item in Windows Start menu.
     Execute the following commands in the new MSYS2 window:
     cd /c/Temp/lua-5.4.3/
mingw32-make MYLDFLAGS=-mwindows mingw

   • Close the MSYS2 console window.

   • You can uninstall "MSYS2" application now at Control Panel -> Programs and Features.

4. Take Lua binaries

   • Open folder C:\Temp\lua-5.4.3\src\
     Sort files by "Date Modified".

   • Find lua.exe among the most recently modified.
     Rename it to wlua.exe

   • Take 2 files: wlua.exe and lua54.dll
     and put them to the folder where Lua binaries should be on your system.

   • You can remove Lua sources now.
     Delete folder C:\Temp\lua-5.4.3\