Delphi 10.2.3: Where is in Delphi the function VarType ()?

Question

I am trying to convert Delphi2005 code to Delphi Tokyo 10.2.3 code. The function VarType is no longer recognized. I need the function VarType to determine the basic type of a variant variable. In general I find, according to many postings, that it should be in the unit System.Variants. However, if I search e.g. in:

http://docs.embarcadero.com/products/rad_studio/delphiAndcpp2009/HelpUpdate2/EN/html/delphivclwin32/!!FUNCTIONS_System.html

It is not in this unit. Furthermore, I cannot find the unit variants, only a unit variant. However, using the unit variant I get a runtime error:

Record, object or class type necessary

. So this doesn't work.

if (System.Variant.VarType(Value)  and varTypeMask) =         
   System.Variant.varString  then  // VarType(Value) unbekannt
begin
  TByte8Array(PRecFORMULA3(PBuf).Value)[0] := 0;
end;

Anyway I don't find VarType in System.variant. Does variants not exist anymore?

Can anyone help me?

Answer 1

The documentation you linked to is quite old. It is for Delphi 2009, which predates the introduction of Unit Scope Names. But even in that old documentation, VarType() is documented as being in the Variants unit (not in the Variant unit, which does not exist).

Unit Scope Names, like System, were added to RTL/VCL unit names in XE2 (thus, the Variants unit became System.Variants).

Embarcadero's newer DocWiki, which replaces the old Docs site, clearly shows that the VarType() function is indeed located in the System.Variants unit.

Make sure that either:

1. you have System.Variants in your uses clause:

   uses
     ..., System.Variants;
   

2. you have System in your project's list of Unit Scope Names, and then you can use Variants in your uses clause:

   uses
     ..., Variants;
   

Either way, you can then use VarType() as expected, without having to fully qualify it:

if (VarType(Value) and varTypeMask) = varString then
begin
  TByte8Array(PRecFORMULA3(PBuf).Value)[0] := 0;
end;