libcoap  4.2.0
Here is a list of all modules:
 Asynchronous MessagingStructure for managing asynchronous state of CoAP resources
 Block TransferAPI functions for handling PDUs using CoAP BLOCK options
 Logging SupportAPI functions for logging support
 DTLS SupportAPI functions for interfacing with DTLS libraries
 DTLS Support (Internal)Internal API functions for interfacing with DTLS libraries
 Event APIAPI functions for event delivery from lower-layer library functions
 Rate ControlThe transmission parameters for CoAP rate control ("Congestion Control" in stream-oriented protocols) are defined in
 Clock HandlingDefault implementation of internal clock
 Option FiltersAPI functions for access option filters
 Pseudo Random NumbersAPI functions for gerating pseudo random numbers
 String handling supportAPI functions for handling strings
 Resource observationAPI functions for interfacing with the observe handling (RFC7641)
 URI Parsing FunctionsCoAP PDUs contain normalized URIs with their path and query split into multiple segments