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I was making an IP scanner , that works with multi-threading.

After running threads I print returned values(a list)

But the functions are running again without returning a list.

It happens when the function is equal to a variable. That takes more time because functions run one by one.

What to do ?

def first_50IP() : prefix = "192.168.1." condition = "Destination host unreachable" condition2 = "Request timed out" list1 = [] for xxx in range(0,50) : ip = prefix + str(xxx) code = "ping " + ip + " -n 1 -l 1" ping = os.popen(code).read() #ping = subprocess.check_output(code).decode('utf-8') if condition not in ping and condition2 not in ping: print(G + ip) list1.append(ip) return list1 def second_50IP() : prefix = "192.168.1." condition = "Destination host unreachable" condition2 = "Request timed out" list2 = [] for xxx in range(50,100) : ip = prefix + str(xxx) code = "ping " + ip + " -n 1 -l 1" ping = os.popen(code).read() #ping = subprocess.check_output(code).decode('utf-8') if condition not in ping and condition2 not in ping: print(G + ip) list2.append(ip) return list2 thread1 = threading.Thread(target=first_50IP) thread2 = threading.Thread(target=second_50IP) thread1.start() thread2.start() thread1.join() thread2.join() print("\nResults : \n") final_ip1 = first_50IP() final_ip2 = second_50IP() print(final_ip1) print(final_ip2)
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You are running the same functions twice. The first time in a dedicated thread and then in the main thread again.

Use executors and futures to avoid that:

with concurrent.futures.ThreadPoolExecutor(max_workers=5) as executor: first = executor.submit(first_50IP) second = executor.submit(second_50IP) print("\nResults : \n") final_ip1 = first.result() final_ip2 = second.result() print(final_ip1) print(final_ip2)

A side note: you can have just one function instead of using two almost identical like this:

def ping_many(start, count) : prefix = "192.168.1." condition = "Destination host unreachable" condition2 = "Request timed out" list1 = [] for xxx in range(start, start+count) : ip = prefix + str(xxx) code = "ping " + ip + " -n 1 -l 1" ping = os.popen(code).read() #ping = subprocess.check_output(code).decode('utf-8') if condition not in ping and condition2 not in ping: print(G + ip) list1.append(ip) return list1

In this case you can submit functions with different parameters to executor like this:

tasks = {} with concurrent.futures.ThreadPoolExecutor(max_workers=5) as executor: for start in [0, 50]: tasks.add(executor.submit(ping_many, start, 50)) print("\nResults : \n") for task in tasks: print(task.result())
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2 Comments

theres an error in tasks.add(executor.submit(ping_many, start, 50)) Instance of 'dict' has no 'add' member
how can i do it to full ip range ? 192.168.1.0 - 192.168.1.255