- void *(*create_field_func)(void *),
- void (*release_field_func)(void *),
- void *(*create_header_field_func)(void *, void *),
- void (*release_header_field_func)(void *),
+ create_field_func create_field_func,
+ release_field_func release_field_func,
+ create_header_field_func create_header_field_func,
+ release_header_field_func release_header_field_func,