TRttiInfo.DynArrayItemSize get 0 when no elType is present

[mksjgj]

function TRttiInfo.DynArrayItemSize: PtrInt;
begin
if DynArrayItemType(result) = nil then
result := 0; --> this is an error !!! Item size is independent of elType
end;

function TRttiInfo.DynArrayItemType(out aDataSize: PtrInt): PRttiInfo;
begin
with GetTypeData(@self)^ do
begin
aDataSize := elSize;
result := pointer(elType); //elType is nil if type does not require cleanup
if result <> nil then
result := PPointer(result)^;
end;
end;

[synopse]

This function does what it is documented to do: " get the dynamic array type information of the stored item"
So if there is no stored item, elType is nil.

What do you want to achieve?
If you want to access the RTTI as mORMot does, use TRttiCustom and its properties, e.g. Cache.ItemSize.

Please use the forum to discuss this.

[mksjgj]

program Project1;

{$APPTYPE CONSOLE}

{$R *.res}

uses
System.SysUtils,
mormot.core.rtti;

type
PSimpleLocator = ^TSimpleLocator;
TSimpleLocator = packed record
Id:Int32;
Pos: Int32;
end;
TSimpleLocatorArray = array of TSimpleLocator;

var
FXLocArrTyp :PRttiInfo;
sz:Integer;
begin
FXLocArrTyp := TypeInfo(TSimpleLocatorArray);

sz := FXLocArrTyp.DynArrayItemSize;
WriteLn('DynArrayItemSize: ItemSize is ' + sz.ToString); //DynArrayItemSize: ItemSize is 0

FXLocArrTyp.DynArrayItemType(sz);
WriteLn('DynArrayItemType: ItemSize is ' + sz.ToString); //DynArrayItemType: ItemSize is 8

WriteLn('You can see, something is wrong!');
end.

[synopse]

I guess you are using Delphi, not FPC?

[mksjgj]

yes delphi 10.3.3

[synopse]

Should be fixed now.

Thanks for the feedback.

But anyway, you should better use TRttiCustom and its properties, e.g. Cache.ItemSize, rather than those lower level functions.