ppsspp/docs/command-line.md

Command-line parsing

All command-line parsing for both the main app and the headless build belongs in Core/CmdLine.cpp / Core/CmdLine.h (CommandLineOptions), not in the platform entry points (Windows/main.cpp, headless/Headless.cpp, UI/NativeApp.cpp, etc.). Don't re-parse argv in those files - add a field to CommandLineOptions instead.

Declaring an option

Most options are declared in the g_autoParams table in CmdLine.cpp as:

{offsetof(...), type, longName, shortName, docString, mode}

mode gates the option to CmdLineMode::Application, ::Headless, or ::Both (the default if the field is omitted from the initializer).

The same long name can be reused for both modes with different types and meanings, because a given Parse() call only matches params whose mode is Both or equal to the current mode. --log is the example to know: a String "log to FILE" option in Application mode, a Bool "full log output" option in Headless mode. They don't collide.

Options that can be repeated (e.g. --ignore TESTNAME, collected into a std::vector<std::string>), or that don't fit the generic single-value table, need manual handling in the else if chain inside CommandLineOptions::Parse() - the same way --graphics= and the boot filenames are handled.

Getting a parsed option into the emulator

ApplyToConfig() is where parsed options are pushed into g_Config / g_logManager. Prefer wiring a new option through there, so every platform gets it for free, rather than reading CommandLineOptions fields ad-hoc at each call site.

NativeInit() in UI/NativeApp.cpp still takes argc/argv, because several platform entry points pass them in, but it shouldn't read them directly: by the time NativeInit() runs, CommandLineOptions should already hold everything.