In the MinGW compiler, what is the -mwindows command, and what does it do?

Question

I was having an issue with a C++ program where when I ran the .exe the program would run and my window for the program would open, but the console would be open on the desktop in the background. I did a google search and found that compiling with the -mwindows command as an argument, removes the console. Which it did. But I'm unsure of what it actually does and I am curious.

Answer 1

It behaves exactly the same as the /subsystem:windows switch described on MSDN .

Basically, it sets the entry point to WinMain (or wWinMain ) instead of main (or wmain ), which results in no console window and some Win32 startup code running to create the arguments passed to WinMain . As Neil says, it does not prevent or enable anything you can't do without it.

A similar switch is -municode to switch between main / WinMain and wmain / wWinMain , which is not mirrorred by the Microsoft tools. These seem to automagically select the one you use).

Answer 2

It says that your application is one using the Win32 API that doesn't need a console window. You use this option when you are writing Windows GUI applications, DLLs and the like, although a console window can be useful when debugging these kinds of applications. Even with this option, you can explicitly create a console window, should your application need one dynamically and, contrariwise, you can call Win32 GUI APIs from a console application.

Answer 3

In Code::Blocks 20.03 (uses the MinGW-W64 gcc compiler project) the project target ( bin/Release ) compiles with -mwindows and the project target ( bin/debug ) compiles without -mwindows. The debug target not only has debugging information in the executable, but it runs with the console window exposed in the background. This is 'highly' useful for debugging, since your app can write to the console debugging messages while your gui app is processing... like an active debugging log. Obviously the console is ugly for release targets. In Code::Blocks the switch -mwindows is set indirectly in the Project properties under the 'build targets' the bin/debug build target is specified as console app, while the bin/release target is specified as gui app.
Back in the day (maybe eight years ago) there was a catch-22; -mwindows was necessary to link the Win32 api (but no console). If you wanted a console AND the Win32 api it didn't work easily; fortunately this is not an issue today... you can mix and match. I generally build my release targets without the console; and I build the debug targets with the console, and I use the console for debugging copiously. marcus