+--- Get protocol entry by name.
+-- @usage This function returns nil if the given protocol is unknown.
+-- @class function
+-- @name nixio.getprotobyname
+-- @param name protocol name to lookup
+-- @return Table containing the following fields: <ul>
+-- <li>name = Protocol Name</li>
+-- <li>proto = Protocol Number</li>
+-- <li>aliases = Table of alias names</li>
+-- </ul>
+
+--- Get protocol entry by number.
+-- @usage This function returns nil if the given protocol is unknown.
+-- @class function
+-- @name nixio.getprotobynumber
+-- @param proto protocol number to lookup
+-- @return Table containing the following fields: <ul>
+-- <li>name = Protocol Name</li>
+-- <li>proto = Protocol Number</li>
+-- <li>aliases = Table of alias names</li>
+-- </ul>
+
+--- Get all or a specifc proto entry.
+-- @class function
+-- @name nixio.getproto
+-- @param proto protocol number or name to lookup (optional)
+-- @return Table (or if no parameter is given, a table of tables)
+-- containing the following fields: <ul>
+-- <li>name = Protocol Name</li>
+-- <li>proto = Protocol Number</li>
+-- <li>aliases = Table of alias names</li>
+-- </ul>
+