Linux read () function

Now, make clear the concept of blocking (block). When a process calls a blocked system function, the process is placed in the sleep state, when the kernel dispatches another process to run until the event that the process waits for (such as receiving a packet on the network, or calling sleep to specify the sleeping time) it is possible to continue running.

So the advantage of blocking is that the operating system will come back to process the data, rather than blocking the user having to write their own polling to process the data.

Reference

[1].http://blog.csdn.net/hjhcs121/article/details/7460738

[2].http://blog.csdn.net/ww2000e/article/details/4497349

Linux read () function