Qt's QMessageBox and QFileDialog ask shell32 for the warning,
information, error and question icons, and the program ends when the
call is missing. The stock icons now map to the matching IDI_ system
icon, loaded at the large or small size with SHGSI_ICON, and the
structure reports the icon's index and user32.dll as its file. The
structure is laid out for the caller's width (0x220 bytes for 64-bit
programs, 0x218 for 32-bit ones), and one of another size is refused
with E_INVALIDARG.
Assisted-by: Claude Code:claude-opus-5-5
AI-Scope: Wrote the implementation from the documented SHSTOCKICONINFO
layout and SIID_/SHGSI_ values, and the 32- and 64-bit
stock_icon_client fixture. Prompt: a Qt program exits when it shows a message box.
Ray Bennett