What kind of loop is for (;;)?
The for(;;) is an infinite loop condition, similar to while(1) as most have already mentioned. You would more often see this, in kernel mutex codes, or mutex eg problem such as dining philosophers. Until the mutex variable is set to a particular value, such that a second process gets access to the resource, the second process keeps on looping, also known as busy wait. Access to a resource can be disk access, for which 2 process are competing to gain access using a mutex such that at a time only one process has the access to the resource.