Python Singleton Mode

1. the python Singleton mode is described here in two ways. One is implemented by createmutex of win32event, and the other is to define a global variable.

The first implementation method can refer to here http://code.activestate.com/recipes/474070-creating-a-single-instance-application/

From win32event import createmutexfrom WIN32API import closehandle, getlasterrorfrom winerror import error_already_existsclass singleinstance: "" limits application to Single Instance "" def _ init _ (Self): Self. mutexname = "testmutex _ {D0E858DF-985E-4907-B7FB-8D732C3FC3B9}" self. mutex = createmutex (none, false, self. mutexname) self. lasterror = getlasterror () def aleradyrunning (Self): Return (self. lasterror = error_already_exists) def _ del _ (Self): If self. mutex: closehandle (self. mutex) # examples # sample usage: # From singleinstance import singleinstancefrom sys import exit # do this at beginnig of your applicationmyapp = singleinstance () # Check is another instance of same program runningif MyApp. aleradyrunning (): Print "another instance of this program is already running" exit (0) # not running, safe to continue... print "no another instance is running, can continue here" # End of http://code.activestate.com/recipes/474070 }}}

2. For method 2, a lot of online methods, here is a simple excerpt, http://dev.firnow.com/course/1_web/webjs/200855/114357.html

 

Code

  Class  Logger (object ):
Log  =  None
@ Staticmethod
  Def  New ():
  If     Not  Logger. log:
Logger. Log =  Logger ()
  Return  Logger. Log
  Def  Write (self, V ):
  Print  STR (Self), V

Log1  =  Logger. New ()
Log1.write (  "  Log1  "  )

Log2  =  Logger. New ()
Log2.write ( "  Log2  "  )

"
Analysis: A simple implementation method is to save the current instance and return the previous instance at the next instantiation. However, thread security cannot be ensured during judgment. Put it here, first of all, there is a train of thought.
  """