プロトコル名とサービス名からサービス情報を収めたservent 構造体を返す
struct servent* FAR getservbyname(
const char* name,
const char* proto
);
----
name
-A pointer to a service name. 

proto
-An optional pointer to a protocol name. If this is NULL, getservbyname() returns the first service entry for which the name matches the s_name or one of the s_aliases. Otherwise getservbyname() matches both the name and the proto.