Why is it inconsistent when using structures as dllcall's arguments

[thqby]

This is ahk code.

Code: Select all

VarSetCapacity(variant, 8+A_PtrSize*2, 0)
NumPut(VT_I4 := 3, variant, 0, "ushort")
NumPut(UIA_EditControlTypeId := 50004, variant, 8, "int")
if (A_PtrSize = 4)
   DllCall(NumGet(NumGet(IUIAutomation+0)+23*A_PtrSize), "ptr", IUIAutomation, "int", UIA_ControlTypePropertyId := 30003, "int64", NumGet(variant, 0, "int64"), "int64", NumGet(variant, 8, "int64"), "ptr*", condition2)
else
   DllCall(NumGet(NumGet(IUIAutomation+0)+23*A_PtrSize), "ptr", IUIAutomation, "int", UIA_ControlTypePropertyId := 30003, "ptr", &variant, "ptr*", condition2)

WINAPI Header definition: IUIAutomation::CreatePropertyCondition(PROPERTYID propertyId, VARIANT value, IUIAutomationCondition **newCondition)
I know that the structure can be split into multiple corresponding values and passed to the dllcall, why is the 64 bit passed into the pointer?

[thqby]

I found the answer here.
https://docs.microsoft.com/en-us/cpp/build/x64-calling-convention?view=msvc-160#parameter-passing

[swagfag]

theres also old threads about this viewtopic.php?f=76&t=60442