AppIsRunning

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Test whether an Application is already running

Here's a unit that works under both Windows and Linux

• There's no need to pass the full application path to the function - the ExeName will usually do. Below code cannot find out its own exename though.

unit uappisrunning;

{$mode objfpc}{$H+}

interface

uses
  Classes, SysUtils
  {$IFDEF WINDOWS}, Windows, JwaTlHelp32{$ENDIF}
  {$IFDEF LINUX},process{$ENDIF};
// JwaTlHelp32 is in fpc\packages\winunits-jedi\src\jwatlhelp32.pas

// Returns TRUE if EXEName is running under Windows or Linux
// Don't pass an .exe extension to Linux!
function AppIsRunning(const ExeName: string):Boolean;

implementation

// These functions return Zero if app is NOT running
// Override them if you have a better implementation

{$IFDEF WINDOWS}
function WindowsAppIsRunning(const ExeName: string): integer;
var
  ContinueLoop: BOOL;
  FSnapshotHandle: THandle;
  FProcessEntry32: TProcessEntry32;

begin
  FSnapshotHandle := CreateToolhelp32Snapshot(TH32CS_SNAPPROCESS, 0);
  FProcessEntry32.dwSize := SizeOf(FProcessEntry32);
  ContinueLoop := Process32First(FSnapshotHandle, FProcessEntry32);
  Result := 0;

  while integer(ContinueLoop) <> 0 do
    begin
    if ((UpperCase(ExtractFileName(FProcessEntry32.szExeFile)) =
      UpperCase(ExeName)) or (UpperCase(FProcessEntry32.szExeFile) =
      UpperCase(ExeName))) then
      begin
      Inc(Result);
      // SendMessage(Exit-Message) possible?
      end;
    ContinueLoop := Process32Next(FSnapshotHandle, FProcessEntry32);
    end;

  CloseHandle(FSnapshotHandle);
end;
{$ENDIF}

{$IFDEF LINUX}
function LinuxAppIsRunning(const ExeName: string): integer;
var
  t: TProcess;
  s: TStringList;

begin
  Result := 0;
  t := tprocess.Create(nil);
  t.CommandLine := 'ps -C ' + ExeName;
  t.Options := [poUsePipes, poWaitonexit];

    try
    t.Execute;
    s := TStringList.Create;
      try
      s.LoadFromStream(t.Output);
      Result := Pos(ExeName, s.Text);
      finally
      s.Free;
      end;
    finally
    t.Free;
    end;

end;
{$ENDIF}

function AppIsRunning(const ExeName: string):Boolean;
begin

{$IFDEF WINDOWS}
  Result:=(WindowsAppIsRunning(ExeName) > 0);
{$ENDIF}

{$IFDEF LINUX}
  Result:=(LinuxAppIsRunning(ExeName) > 0);
{$ENDIF}

end;
end.

See also

• UniqueInstance