Re: [fltk.coredev] What does the "fluid-cmd" exe do on the WIN32 builds?

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Re: What does the "fluid-cmd" exe do on the WIN32 builds? Albrecht Schlosser 05:58 Oct 02 top right image
On 10/2/22 08:05 Greg Ercolano wrote:

On 10/1/22 05:32, Albrecht Schlosser wrote:

On 10/1/22 14:00 Ian MacArthur wrote:

The only difference is that it's a Windows Console (-mconsole) rather than a Windows GUI (-mwindows) executable. This was done on request (by Greg) because some fluid issues (e.g. not being able to access remote file systems or other errors) would not display an error message if built as GUI exe as it was before.

    Yes, though more importantly: the Makefile would not get a proper exit code from fluid
    when it failed, causing a build invoking e.g. 'fluid -c foo.fl' to sail right through
    even if the creation of .cxx/.h failed due to a write error.

Oh, thanks, I didn't know that fact.

Anyway, I noticed this because a 32-bit mingw checkout choked at build for me - stuck in fluid-cmd.exe, just sitting there... indefinitely...

    Hmm, I'd be curious what fluid-cmd's were being invoked (was it the -c flag? e.g. "fluid-cmd -c xyz.fl"?)

During the build only `fluid-cmd -c xxx.fl` commands are executed.

    For sure that should just write out files, print errors to stdout/err and /exit/, and not pop any GUI dialogs
    so as to prevent any kind of interaction with the GUI, ...

    fluid should be avoiding ANY gui calls during a -c operation; all -c flag handling in main()
    should precede any initialization or use of FLTK calls.

    Hopefully there's no global window manager stuff being triggered before main() in fluid,
    otherwise there might be contention with the window manager in a parallel build
    scenario, where two or more fluids run at once, contending for the window manager
    and blocking each other. I hope that's not the case.

... And why does it hang?

... I have no idea how to debug this (other than printf statements in fluid, maybe).

    I'd probably suggest attaching a debugger to one of the hung processes
    to see what it's stuck executing.

I know that this is possible but I never tried this. Seems like something I need to learn so I can try this the next time my build hangs in fluid-cmd. Or maybe Ian, could you try it in your situation?

    If it's hung during a -c command in window manager stuff, then we may have
    to move the -c option to a separate binary that doesn't link with fltk, just so
    it can be a purely 'headless' command line tool.

This is something Matt did always take care of and I test this from time to time. It's easy to test in a "normal" (non-wayland) build on Linux by deassigning the DISPLAY environment variable, e.g. in bash:

$ unset DISPLAY
$ cd fluid
$ ./fluid -c about_panel.fl 

You can test this yourself. If fluid (or fluid-cmd) returns w/o error message it works, obviously w/o opening the display. If you run `fluid` only you'll see the error message:

$ ./fluid  
Can't open display:  

Note: for a wayland (hybrid) build you'd have to assign FLTK_BACKEND=x11 to enforce the x11 backend.

Although we're talking in this thread about Windows it shouldn't be different on that platform. I don't know how to *verify* this on Windows though other than adding printf's (or setting a breakpoint in a debugger) at appropriate places in the code.

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