libcoap implements a lightweight application-protocol for devices
that are constrained in their resources such as computing power,
RF range, memory, bandwith, or network packet sizes.
This protocol, CoAP, was standardized in the IETF as RFC 7252.

By default, the API documentation is not built, as it's rather
resource-intensive, and not required unless you're a developer. If
you need the API docs, install graphviz, then run this build with
APIDOC=yes in the environment.