Modern C
Start with NNG.
NNG is the current C implementation of the Scalability Protocols. This is the complete pattern-based tutorial migrated from lib.nanomsg.org and updated to build against NNG main.
Each guide includes the rationale, complete C program, compilation command, invocation, and representative output from the original tutorial. Start with PAIR, then choose the topology your application needs.
The examples have been modernized for NNG main: protocol declarations now come from nng/nng.h, socket options use typed socket functions, subscriptions use nng_sub0_socket_subscribe, and receives use nng_recvmsg internally rather than the removed NNG_FLAG_ALLOC API.