Create Single Instance Python Application in Windows

Source by Dragan Jovelic.

from win32event import CreateMutex

from win32api import CloseHandle, GetLastError

from winerror import ERROR_ALREADY_EXISTS

class 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)

#---------------------------------------------#

# sample usage:

#

from singleinstance import singleinstance

from sys import exit

# do this at beginnig of your application

myapp = singleinstance()

# check is another instance of same program running

if 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"