Re: [hatari-devel] Hatari debug mode

[Vincent Rivière <vincent.riviere@xxxxxxxxxxx>]

On 31/07/2025 at 21:08, Nicolas Pomarède wrote:
> regarding this console issues, do you know if there's a way to detect in 
> which "context" Hatari was launched ? ie from an already opened console or 
> by clicking on its icon (or using windows menu to launch it) ?

Unfortunately, Windows isn't designed to do that at runtime. Availability of 
a console is normally specified at link-time: either "console application" 
or "GUI application". This sets a specific bit in the .exe header.

- If the program is a "console application" (compiled with gcc -mconsole), 
Windows ensures there is always a console to perform text I/O. If the 
program is run from a shell (i.e. cmd.exe), the shell's console is reused. 
If the program is double-clicked from the Explorer, a new console is opened. 
printf() output is of course directed to that console. This is the classic 
UNIX behaviour, except that the console is automatically opened by the 
operating system if there is none. This is a good thing for text-mode 
programs, but undesirable for GUI programs.

- If the program is a "GUI application" (compiled with gcc -mwindows), no 
console is reused or opened on startup. printf() does nothing, as console 
I/O isn't initialized. Furthermore, if run from a cmd, the program is 
started asynchronously (like "&" suffix on bash shell), so the user can type 
new commands without having to wait for the program's end. Such programs can 
be run synchronously by using the "start /w" prefix, such as "start /w 
notepad". On the contrary, when programs are run from a .bat file, they are 
always run synchronously.

When run from cmd, a GUI program can attach itself to the cmd's console 
using AttachConsole(ATTACH_PARENT_PROCESS). Then it can reinitialize stdout 
using GetStdHandle / freopen_s / setvbuf (*), so it can use printf. But this 
isn't ideal, because the starting cmd isn't aware of that special behaviour 
going to happen, so it starts the program asynchronously anyway. And as 
Thorsten mentioned, such hacks don't work well with MinTTY (the terminal 
used by Cygwin and MSYS2).

(*) https://forum.qt.io/topic/144399/command-line-and-gui-at-same-time/4

The most common solution is to avoid those hacks, and simply provide 2 
executables. One compiled with -mconsole (to run with console), and the 
other one with -mwindows (to run without console). This is the solution 
chosen by the Java Runtime Environment. On UNIX systems, there is a single 
"java" command, which may or may not produce output to the console. On 
Windows systems, "java.exe" is a console application, so output can be 
displayed. And a second executable "javaw.exe" is provided, that one being a 
GUI application, silently ignoring all console output. So the user is free 
to use "java" or "javaw" depending on the context. Hatari could to the same, 
with hatari.exe and hatariw.exe executables.

--
Vincent Rivière