SRF question

Hi everyone.

I need to create a C function that returns a row, and the type of this row must be the same of a type that I've created using CREATE TYPE.

I've seen the function:
TupleDesc TypeGetTupleDesc(Oid typeoid, List *colaliases)
but I don't understand two things:

1)I just know the name of the type, not its oid... woud it be ok if I execute a SELECT on pg_type asking for typname to find the oid of the type I want to return? or is there any function like RelationNameGetTupleDesc (maybe TypeNameGetTupleDesc) that I can call passing just the typename as a char *?

2)in case TypeGetTupleDesc is the only option, what is the second argument?

Thanks in advance.