Method Name:
poll()
Overview:
- Using select() the number of descriptors that can be monitored is dependent on the FD_SETSIZE of the platform which is normally set to 1024. If a network program has to monitor a number of descriptors beyond FD_SETSIZE, select() can not be used.
- Using the method poll() there is no limit on the number of descriptors.
- poll() is event based.
- Using poll() a set of I/O events can be registered for a descriptor through the register() function.
- A call to method poll(timeout) will return a list of tuples where each tuple is comprised of a file descriptor and the event. If no event occurred within the time as specified by timeout, an empty list will be returned.
- Iterating through the list of tuples, I/O events can be processed for specific descriptors.
Parameters:
Not applicable
Return Value:
Returns a Polling object
Example:
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import select import socket import os
serverSocket = socket.socket(socket.AF_INET, socket.SOCK_STREAM) serverSocket.setsockopt(socket.SOL_SOCKET, socket.SO_REUSEADDR, 1)
ipAddress = '127.0.0.1' portNumber = 20000
serverSocket.bind((ipAddress, portNumber)) serverSocket.listen()
pollerObject = select.poll() pollerObject.register(serverSocket, select.POLLIN)
while(True): fdVsEvent = pollerObject.poll(10000) for descriptor, Event in fdVsEvent: print("Got an incoming connection request") print("Start processing") # Do accept() on server socket or read from a client socket
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