Windows Curses Display Infinite Loop

Host environment

• Operating system: Windows 10 22H2
• OS/kernel version: 19045.5608
• Architecture: x86-64
• QEMU flavor: qemu-system-x86_64
• QEMU version: QEMU emulator version 9.2.91 (v10.0.0-rc1-12076-g50ecdaef16)
• QEMU command line:

  ./qemu-system-x86_64 -display curses

Emulated/Virtualized environment

• Operating system: N/A
• OS/kernel version: N/A
• Architecture: x86-64

Description of problem

The out-of-the-box qemu-system-x86_64 -display curses on Windows loops forever while displaying "VGA Blank Mode" instead of booting like qemu-system-x86_64 does.

This is caused by an infinite loop in the below simplified code in curses_refresh in ui/curses.c:

    int chr;
    // ...trimmed
    while (1) {
        /* while there are any pending key strokes to process */
        chr = console_getch(&maybe_keycode);

        if (chr == -1) 
            break;
    // ...trimmed
    }

console_getch has return type wint_t. However, on Windows, wint_t is unsigned short. Therefore when console_getch returns -1, the -1 value of unsigned short will be silently converted into the int value 65535. This causes 65535 == -1 to always be false, and the loop will never break. I can send a patch to qemu-devel which retypes chr to wint_t and replaces occurences of -1 with WEOF (an alias for (wint_t) -1).

Steps to reproduce

1. Install qemu-w64-setup-20250326.exe Windows qemu from https://qemu.weilnetz.de/w64/2025/
2. Run ./qemu-system-x86_64 -display curses
3. "VGA Blank Mode" will appear on the screen forever

Additional information