How to control concurrency access on a variable in NodeJS?

Question

For example:

var i = 0;
while(true)
 http.request('a url', callback_f);
function **callback_f**(){
 **i++**;
}

In my simple imaginary example, some request might try to increase i's value in the same time, How can I write a code which is thread safe in NodeJS?

• bvj: stackoverflow.com/questions/5200821/…

Answer 1

You do not have to worry about threads in Node.js. Node.js handles all calls within a single threaded environment.

• Ali Bahraminezhad: Sounds awesome! Then I don't need to write something like delegation(in .netframeowrk) in NodeJS?
• Hakan Serce: I do not know .NET delegation, but in Node.js almost all IO functions are implemented asynchronously which allows the system to call the callbacks in a single threaded manner. This is one of the most powerful properties of Node.js actually.
• thefourtheye: @HakanSerce Not almost all, all
• Hakan Serce: @thefortheye There are actually several synchronous APIs in Node.js. Check this for instance, nodejs.org/docs/v0.3.1/api/fs.html#fs.readSync
• thefourtheye: @HakanSerce What I meant is, there is no Node.js function which does only synchronous IO (it may have Sync counterparts)