COM Method Return Types

[Thomas Tierney]

I would like to return a boolean value from a COM Method. This is essentially a VARIANT of type VT_BOOL. How do I tell the compiler to create this type in the typelib, or will I manually have to create the TYPELIB with this value?

[Steven Pringels 3]

Thomas,

Maybe try

Method MyBoolean() as Variant

 Dim pVariant AS VARIANTAPI PTR
 Dim vBoolean as VARIANT

 pVariant = VarPtr(vBoolean)
 pVariant.vt = %VT_BOOLEAN

 vBoolean = 1 

 Method = vBoolean

End Method

Something like this ?

[Dominic Mitchell]

I don't think so, because for a dual interface, he wants something like this in the *.idl

    [id(0x00000008), propget, helpstring("Returns/sets a value which specifies if a Node object is locked.")]
    HRESULT Locked([out, retval] VARIANT_BOOL* fLocked);

Using low-level COM, this would be coded something like this

FUNCTION treeINode_get_Locked(BYVAL pThis AS DWORD, fLocked AS INTEGER) AS LONG

  LOCAL pttid     AS INode PTR

  pttid = pThis

  IF VARPTR(fLocked) = %NULL THEN
    FUNCTION = %E_POINTER
    EXIT FUNCTION
  END IF

  IF (@pttid.dwState AND %TIS_LOCKED) THEN
    fLocked = &HFFFF%
  ELSE
    fLocked = &H0000%
  END IF

  FUNCTION = %S_OK

END FUNCTION

How do we code this in PB9 COM to get the same output in the *.idl as shown above?

Or, if this was a property, output similar to this

[id(0x00000002), helpstring("Sets or returns my flag."), helpcontext(0x000003f0)]
VARIANT_BOOL MyBoolean;

[Thomas Tierney]

Looks like it can be done only if I create the IDL manually and then create the TLB seperately.


Thanks ALL!