Share via

Passing a Single UDT

  • Article

For passing a single UDT for v-table binding, the designer of the server describes the data types of the UDT in a IDL file. The client and server will then simply declare the UDT and pass it to one another.

The following is an example of a type defined for a UDT:

library udttest
{
   typedef [uuid(C1D3A8C0-A4AA-11D0-819C-00A0C90FFFC3)] struct_tagUDT {
      unsigned long a1;
      BSTR pbstr;
   } UDT;

The structure, named UDT, is defined with two data types, an unsigned long and a BSTR. The struct tagTEST, which is the UDT, is declared and assigned some values. Error checking is omitted for brevity.

typedef struct tagTEST {
    ULONG a1;
    BSTR pbstr;
} TEST;
TEST a, b;
a.a1 = 0x1234;
a.pbstr = SysAllocString(L"Hello");
b.a1 = 0;
b.pbstr = NULL;

Then the structure is passed to a method:

pRecInfo->RecordCopy(&a, &b);

GetRecordInfoFromTypeInfo

GetRecordInfoFromGuids

LoadRegTypeLib

IDispatch::GetTypeInfo

ITypeInfo