c_gtk_cell_area_context_get_preferred_width_for_height

Undocumented in source but is binding to C. You might be able to learn more by searching the web for its name.
__gshared extern (C)
void function(GtkCellAreaContext* context, int height, int* minimumWidth, int* naturalWidth) c_gtk_cell_area_context_get_preferred_width_for_height;

Meta