Back in the System Programming section we took quite a detailed look at the more important system calls provided by Linux. The list we looked at does not represent the complete list of available system calls, nor could it, as this list is not fixed in size but can be extended as the need arises. Having said this, the list of system calls does not get extended all that often, but it has happened from time to time.
This chapter takes a look at the basic mechanism used by Linux to execute its system calls and then goes on to explain how you could add system calls of your own to the Linux kernel.