O'Reilly logo

Hands-On System Programming with Linux by Kaiwan N Billimoria

Stay ahead with the world's most comprehensive technology and business learning platform.

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, tutorials, and more.

Start Free Trial

No credit card required

System calls

System calls are actually kernel functionality  that can be invoked from userspace via glibc stub routines. They serve a critical function; they connect userspace to kernel-space. If a user program wants to request something of the kernel (read from a file, write to the network, change a file's permissions), it does so by issuing a system call. Therefore, system calls are the only legal entry point to the kernel. There is no other way for a user-space process to invoke the kernel.

For a list of all the available Linux system calls, see section 2 of the man pages (https://linux.die.net/man/2/). One can also do: man 2 syscalls to see the man page on all supported system calls

Another way to think of this: the Linux kernel internally ...

With Safari, you learn the way you learn best. Get unlimited access to videos, live online training, learning paths, books, interactive tutorials, and more.

Start Free Trial

No credit card required