- Both calls read the host's protocols database into one PROTOENT the process reuses, as Winsock reuses its per-thread one: the name, an empty list of aliases and the protocol number.
- The record keeps its pointers, so the 32-bit and 64-bit layouts are written apart; a protocol the database does not list answers NULL with WSANO_DATA, as the services calls beside them do.
- The new guest fixture protocol_client.c checks that both spellings of a protocol name the same record, that a second call reuses it, and that an unlisted name and an unlisted number are refused. It is built for 64-bit and 32-bit callers.
Assisted-by: Claude Code:deepseek-v4.1-flash-1017
AI-Scope: Wrote the two handlers next to the existing getservbyname ones, the PROTOENT writer for both pointer widths, and the guest fixture; checked with ctest (native_protocol_database_client, native_protocol_database_client_x32).
