# 2015-07-18

Today I experimented with poll(2) and finally understood what tasks are 
fulfilled by libraries such as libuv, libevent and libev (libuv is a key 
part of todays node.js, before libuv it was libev) .

Using poll it is possible to watch an array of file descriptors. poll will 
block until a file descriptor is ready for a non blocking operation. Once
that happens poll will return with information on which option is possible
without a block now.

Libraries such as libevent enable event-based programming features using 
calbacks. For example it is possible to execute an asynchronous file or
network operation. Once the operation has been executed a callback will be
invoked.

node.js contains a lot of APIs for file or network operations. Today, libuv 
is used as the interface from the JavaScript world (V8) into the ``real''
world.