Ttk_CreateTheme, Ttk_GetTheme, Ttk_GetDefaultTheme,

Ttk_Theme Ttk_CreateTheme(interp, name, parentTheme);
Ttk_Theme Ttk_GetTheme(interp, name);
Ttk_Theme Ttk_GetDefaultTheme(interp);
Ttk_Theme Ttk_GetCurrentTheme(interp);

Tcl_Interp * interp (in)

The Tcl interpreter in which to register/query available themes.

Ttk_Theme parentTheme (in)

Fallback or parent theme from which the new theme will inherit elements and layouts.

const char * name (in)

The name of the theme.

Ttk_RegisterLayout, Ttk_BuildLayout