Problem Statement

This task is to determine if there is only one instance of an application running. If the program discovers that an instance of it is already running, then it should display a message indicating that it is already running and exit.

Let's start with the solution:

#MyApp="MyLittleApp"
Mutex=CreateMutex_(0,1,#MyApp)
If GetLastError_()=#ERROR_ALREADY_EXISTS
  MessageRequester(#MyApp,"One instance is already started.")
  End
EndIf

; Main code executes here

ReleaseMutex_(Mutex)
End