My experience with C was a long time ago so forgive me if this is of
no relevance.

WriteLog('Begin of isc_attach_database');
Result := isc_attach_database(StatusVector, DBNameLength, DBName,
DBHandle, ParmBufferLength, ParmBuffer);
WriteLog('End of isc_attach_database');

Does C have exceptions? If so, is it possible that attach_database is
firing one so the second writelog is not called?

Adam