How can I run a single instance of my Delphi application on Linux?

I have seen that on Windows it is possible to achieve this through the use of TMutex or through the JclAppInst library, I have not found anything about Linux. The JclAppInst library is not usable on linux, while for what concerns the mutex using this code...

var
  LMutex : TMutex;
begin
  LMutex := TMutex.Create(nil, True, 'D4904154-E778-4762-9C74-BEB567DC4AA4');
  if GetLastError <> 183 then
  begin
    //...do something
  end;
  FreeAndNil(LMutex);  
end;

...I get the following error message:

Named synchronization objects not supported on this platform

CodePudding user response：

As suggested by @AmigoJack, I solved it by locking the same file.

uMyMutex.pas:

unit uMyMutex;

interface

uses
  Classes,
  SysUtils,
  DateUtils;

type
  TMutex = class
  private
    FFilePath: string;
    FFileStream: TFileStream;
  public
    constructor Create(const AName: string);
    destructor Destroy; override;
  end;

implementation

function GetTempDir: string;
begin
  Result := '/tmp/';
end;

constructor TMutex.Create(const AName: string);
var
  LMask: UInt16;
begin
  inherited Create;
  FFileStream := nil;
  FFilePath := IncludeTrailingPathDelimiter(GetTempDir)   AName   '.pid';
  LMask := fmOpenReadWrite or fmShareExclusive;
  if not FileExists(FFilePath) then
    LMask := LMask or fmCreate;
  FFileStream := TFileStream.Create(FFilePath, LMask);
end;

destructor TMutex.Destroy;
begin
  FreeAndNil(FFileStream);
  inherited;
end;
end.

main.pas:

program Test;

uses
  System.Classes,
  uMyMutex;

var
  LPidFileName: string;
begin
  LPidFileName := 'test';
  try
    with TMutex.Create(LPidFileName) do
      try
        //...do something
      finally
        Free;
      end;
  except
    on E: EFOpenError do
    begin
      Writeln(Format('Process already running [%s]; %s', [E.ClassName, E.Message]));
    end;
  end;
end.