IsWin64

function IsWin64: Boolean;

Returns True if system is running a 64-bit version of Windows that provides the API support Inno Setup requires to perform 64-bit installation tasks. If False is returned, you cannot utilize any of Inno Setup's 64-bit-only features.

It is possible for this function to return False if the user is running an early version of 64-bit Windows, such as the Itanium edition of Windows Server 2003 without Service Pack 1. Such older versions lack APIs that Inno Setup requires (e.g. RegDeleteKeyEx).

begin
  // Check IsWin64 before using a 64-bit-only feature to
  // avoid an exception when running on 32-bit Windows.
  if IsWin64 then
  begin
    MsgBox('64-bit program files reside in: ' +
      ExpandConstant('{pf64}'), mbInformation, MB_OK);
  end;
end;

Is64BitInstallMode
ProcessorArchitecture