Expected error return codes not defined

The majority of the api function calls return 'socket_error_t' however there is no documentation that states what the expected error codes for each function should be under particular error conditions.

Start by locating the API function declarations that return socket_error_t and the definitions of the error codes. Review each function's documented error conditions and record the expected code for every case. Done means the API documentation consistently specifies these return codes; the issue does not name a file or test to run.

Written by the indexing model from the issue text.