Uncertain Binary Thoughts » C

small epoll wrapper

Ankur Shrivastava — Sat, 12 Mar 2011 21:32:24 +0000

I remember my first encounter with epoll some time back trying to get a simple server working, implementing a proxy and then a few days back i saw one of my friend trying to get started with epoll, which made me think it will be good to have a simple wrapper around epoll which will allow me to get started with the application and not worry about epoll specifics and at the same time providing enough control, so i wrote a small wrapper with callbacks, which has been quite helpful for my epoll usage, here is the interface poll.h

code and a sample can be found on github

PS – just checkout libevent which is an awesome battle tested event notification library, and a quick getting started

Simple hash tables in c

Ankur Shrivastava — Fri, 11 Mar 2011 14:07:46 +0000

I was working on a code where i had to lookup a structure based on the file descriptor (socket) again and again in a code, i was using a linked list initially but as the nodes grew i knew i should use a hash table, so i wrote a simple hash table implementation which did the work.
its a just works implementation there are a lot of thing which can be added like a perfect hash function but as long as hash table is not the bottle neck this should work, code can be found on github
file hashtable.h contains the definition

file hashtable.c contains the implementaion

file Makefile is the makefile

file main.c contains the sample

file debug.h contains some debugging options

Simple Finite State Machines in C

Ankur Shrivastava — Sun, 04 Apr 2010 21:42:15 +0000

I was having discussion about State Machines with one of my friend, regarding pro’s and con’s of implementing programs as Sate Machines, it was then that i realised there is no simple way to implement programs as Finite State Machines, so here is a very basic implementation of FSM in C

file: fsm.h contains the function definition for our FSM

file: fsm.c contains the function implementation for our FSM

file: main.c contains an example on how this FSM can be used

PS – If you are reading this post on a blog aggregator like planet you can view full post here

Getting started with pthread

Ankur Shrivastava — Thu, 24 Sep 2009 19:38:34 +0000

Recently i have started coding in C a lot and what i came across from a lot of people is that doing Threading in C is very hard, is it really like that? here is a simple Pthread program that should clear that up

get it here

in the above program i have just created 2 threads and passed thr1 ( = 1 ) and thr2 ( = 2 ) values as parameters the function void * thread ( void * ptr ) is executes as a separate thread, we create two thread objects thread1 and thread2, and start threads using pthread_create function passing thread object, function pointer and parameters as arguments, here NULL specifies default attributes for the thread, we can change this by passing pthread_attr_t structure instead of NULL.
we wait for the threads to finish using the pthread_join function
One major problem that is faced by most of the people is of using a library which is not a thread safe library, so you need to be careful about the libraries you use in your program, if not sure about a particular library being thread safe, just assume it not to be thread safe

PS – No updates from a long time as i dont have a proper net connection ….