How to check if a process is running using Delphi?

Question

Similar to this question, but in Delphi:

http://stackoverflow.com/questions/51148/how-do-i-find-out-if-a-process-is-already-running-using-c

I have an updater program, I want it to check the program its about to update is not currently running, preferably it would check all users, not just current user.

Answer 1

from: http://www.delphitricks.com/source-code/windows/check_if_a_process_is_running.html

uses TlHelp32; 

    function processExists(exeFileName: string): Boolean; 
var 
  ContinueLoop: BOOL; 
  FSnapshotHandle: THandle; 
  FProcessEntry32: TProcessEntry32; 
begin 
  FSnapshotHandle := CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0); 
  FProcessEntry32.dwSize := SizeOf(FProcessEntry32); 
  ContinueLoop := Process32First(FSnapshotHandle, FProcessEntry32); 
  Result := False; 
  while Integer(ContinueLoop) <> 0 do 
  begin 
    if ((UpperCase(ExtractFileName(FProcessEntry32.szExeFile)) = 
      UpperCase(ExeFileName)) or (UpperCase(FProcessEntry32.szExeFile) = 
      UpperCase(ExeFileName))) then 
    begin 
      Result := True; 
    end; 
    ContinueLoop := Process32Next(FSnapshotHandle, FProcessEntry32); 
  end; 
  CloseHandle(FSnapshotHandle); 
end; 

procedure TForm1.Button1Click(Sender: TObject); 
begin 
  if processExists('notepad.exe') then 
    ShowMessage('process is running') 
  else 
    ShowMessage('process not running'); 
end;

Answer 2

If you're writing a bit of auto-updating code, you could also consider making a connection of some sort to your application and telling it to shut itself down.

This could e.g. involve posting a message to the main window of your application telling it to shut itself down. Or opening an IPC pipe etc.