I define this struct in my IDL: typedef struct PATIENT_INFO { [string] wchar_t wszLastName[ 50 ]; [string] wchar_t wszPatientID[ 30 ]; } PATIENT_INFO; When I compile I get this error: midl\oleaut32.dll : error MIDL2020 : error generating type library : LayOut failed on struct : __MIDL___MIDL_itf_PatientTestSvr_0000_0001 When I take out the [string] attribute it compiles fine. It is my understanding that the [string] attribute means only the NULL terminated string itself will get marshalled and not the whole buffer (which is the behavior I want). Is my understanding correct and how can I get this to compile? Glenn Wardius GE Medical Systems