Question

I have a console app that must disable or enable some operations when output is redirected (externally) to a file or pipe (myapp.exe > Foo.bar)

How I can check if my Delphi console app is redirected to a file or pipe?

Answer 1

you can use the GetStdHandle and GetFileType functions.

first you retrieve the console output handle using the GetStdHandle function and then you can check the type of the handle with the GetFileType function.

{$APPTYPE CONSOLE}

{$R *.res}

uses
  Windows,
  SysUtils;


function ConsoleRedirected: Boolean;
var
  FileType : DWORD;
begin
  FileType:= GetFileType(GetStdHandle(STD_OUTPUT_HANDLE));
  Result  := (FileType=FILE_TYPE_PIPE) or (FileType=FILE_TYPE_DISK);
end;


begin
  try
    if ConsoleRedirected then
      Writeln('Hello From File')
    else
      Writeln('Hello Console');
  except
    on E: Exception do
      Writeln(E.ClassName, ': ', E.Message);
  end;
end.