Hi all! I have a more complex typedef: typedef struct amqp_frame_t_ { uint8_t frame_type; /* 0 means no event */ amqp_channel_t channel; union { amqp_method_t method; struct { uint16_t class_id; uint64_t body_size; void *decoded; amqp_bytes_t raw; } properties; amqp_bytes_t body_fragment; struct { uint8_t transport_high; uint8_t transport_low; uint8_t protocol_version_major; uint8_t protocol_version_minor; } protocol_header; } payload; } amqp_frame_t; I am struggling with the contained structs properties and payload ... How to define them??? Thanks for any hints! Regards Frank