Specifies the type of function which is called when an extended
error instance is copied. It is passed the pointer to the
destination error and source error, and should copy only the fields
of the private data from @src_error to @dest_error.
Normally, it is better to use G_DEFINE_EXTENDED_ERROR(), as it
already takes care of getting the private data from @src_error and
@dest_error.
Specifies the type of function which is called when an extended error instance is copied. It is passed the pointer to the destination error and source error, and should copy only the fields of the private data from @src_error to @dest_error.
Normally, it is better to use G_DEFINE_EXTENDED_ERROR(), as it already takes care of getting the private data from @src_error and @dest_error.