static string to create a #GQuark from
size of the private error data in bytes
function initializing fields of the private error data
function copying fields of the private error data
function freeing fields of the private error data
#GQuark representing the error domain
2.68
This function registers an extended #GError domain.
@error_type_name should not be freed. @error_type_private_size must be greater than 0.
@error_type_init receives an initialized #GError and should then initialize the private data.
@error_type_copy is a function that receives both original and a copy #GError and should copy the fields of the private error data. The standard #GError fields are already handled.
@error_type_clear receives the pointer to the error, and it should free the fields of the private error data. It should not free the struct itself though.
Normally, it is better to use G_DEFINE_EXTENDED_ERROR(), as it already takes care of passing valid information to this function.