The GError structure contains information about an error that has occurred.
GError
parameter error_type_init: ErrorInitFunc
error_type_init
error code, e.g. %G_FILE_ERROR_NOENT
error domain, e.g. %G_FILE_ERROR
human-readable informative error message
Makes a copy of @error.
Frees a #GError and associated resources.
Returns true if @error matches @domain and @code, false otherwise. In particular, when @error is null, false will be returned.