E2189 Thread local variables cannot be local to a function (Delphi)
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Thread local variables must be declared at a global scope.
 
program Produce;
  procedure NoTLS;
    threadvar
      x : Integer;
  begin
  end;
begin
end.
A thread variable cannot be declared local to a procedure.
 
program Solve;
  threadvar
    x : Integer;
  procedure YesTLS;
    var
      localX : Integer;
  begin
  end;
begin
end.
There are two simple alternatives for avoiding this error. First, the threadvar section can be moved to a local scope. Secondly, the threadvar in the procedure could be changed into a normal var section. Note that if compiler hints are turned on, a hint about localX being declared but not used will be emitted.