gegl-operation-property-keys
void gegl_operation_class_set_property_key (GeglOperationClass *klass, const gchar *property_name, const gchar *key_name, const gchar *value);
GeglOperationClass *klass
const gchar *property_name
const gchar *key_name
const gchar *value
const gchar * gegl_operation_class_get_property_key (GeglOperationClass *operation_class, const gchar *property_name, const gchar *key_name);
GeglOperationClass *operation_class