Add "--no-console" compile flag

[MetabaronCZ]

Hello.
I am using FFI module with SDL3 library and compiling *.exe file on Windows 10.
When double clicking on resulting *.exe file the SDL3 window opens along with console window (the console window is unwanted).

I had similar problem when using SDL3 with C++ (on Windows). The solution was GCC compile flag called "-mwindows". If I understand correctly, this flag tells OS that the application is not terminal based, but graphical.

It is possible to implement this?

My suggestion for resulting compile command:

tjs compile --no-console main.js main.exe

[saghul]

Hum that's a tricky one! When building the executable we are not really compiling anything, the JS code is packed and appended to the exe and there is a bit of bootstrap code to read it.

So that would mean the windows CLI would need to be compiled with that flag.

[MetabaronCZ]

I see. I would have to build my own "tjs.exe" file.
OK, if you think this is too much, you can close the ticket.
Thanks for info.

[saghul]

Let's keep it open for a bit, no problem.

[ReTobias]

The windows "subsytem" is controlled by a single 16bit value in a windows PE (Portable executable)
Fox x86_64 executables, flipping the byte at address 0x17C from 3 (console/CUI) to 2 (GUI) will do the trick.

script that walks through the PE file to find the subsystem and flips the 3 to 2:

import assert from 'tjs:assert';

const tjs_executable = "tjs.exe";
const out_executable = "tjs_win.exe";

try {
    const buffer = await tjs.readFile(tjs_executable);
    const dv = new DataView(buffer.buffer, buffer.byteOffset, buffer.byteLength);

    // Check if we got MZ magic
    const mz_magic = dv.getUint16(0, false); //Read as Big endian to preserve byte order
    assert.ok(mz_magic == 0x4D5A, `${tjs_executable} does not start with a MZ DOS stub header\n(4D 5A \"MZ\" should be first two bytes of file)`);

    // Get new exe header at offset 0x3C
    const e_lfanew_offset = dv.getUint32(0x3C, true);

    // Check if we got PE magic
    const pe_magic = dv.getUint32(e_lfanew_offset, false); //Read as Big endian to preserve byte order
    assert.ok(pe_magic == 0x50450000, `${tjs_executable} does not have PE header at expected offset:${e_lfanew_offset.toString(16)}  \n(50 45 \"PE\" should be first two bytes at offset)`);

    // Optional header should be at e_lfanew + 24 bytes (size of IMAGE_FILE_HEADER)
    const optional_header_offset = e_lfanew_offset + 0x18;

    // Check if we got a valid optional header magic number
    const oh_magic = dv.getUint16(optional_header_offset, false); //Read as Big endian to preserve byte order
    assert.ok(
        oh_magic == 0x0B02 // PE32+ executable
        , `${tjs_executable} does not have a valid optional header for a 64bit executable\nFound: 0x${oh_magic.toString(16).toUpperCase().padStart(4, '0')} at offset 0x${optional_header_offset.toString(16)}. Expected: 0x0B02`
    );

    // Subsystem should be at optional_header + 68 bytes (IMAGE_OPTIONAL_HEADER64.Subsystem)
    const subsystem_offset = optional_header_offset + 0x44;
    const subsystem = dv.getUint16(subsystem_offset, true);
    assert.eq(subsystem, 3, `${tjs_executable} does not have subsystem set to 3 (IMAGE_SUBSYSTEM_WINDOWS_CUI)`);

    // Actually set subsystem to 2 for gui only applications (IMAGE_SUBSYSTEM_WINDOWS_GUI)
    dv.setUint16(subsystem_offset, 2, true);

    // We are done, write the file. 
    tjs.writeFile(out_executable, buffer);
    console.log(`Written ${out_executable} to disk.`);
} catch (e) {
    console.error(`\x1b[33m${e.message}\x1b[0m`);
    console.error(e.stack);
}

But if you control the executable and it's always going to be a 64bit x86 application, the subsystem byte will always be at address 0x17C

Then your tpk app main.js can look something like this:

import { dlopen } from 'tjs:ffi';
const { symbols } = dlopen('user32', {
    MessageBoxA: { args: ['ptr', 'string', 'string', 'u32'], returns: 'i32' }
});
console.log('Hello from tpk!');
symbols.MessageBoxA(null, "Hello GUI", "A message box", 0);

compile keeps on working: (Obviously the gui tjs will not output the errors to the console)

tjs_win app compile my_gui_messagebox.exe

When you double click the resulting executable in explorer, no console window will pop up.

[saghul]

Impressive!