Linux-specific IA-32 examples without external libraries like libc.
Use a libc for OS-portable code instead.
You can also compile and run this in Linux x64-64, which is able to run 32-bit. TODO: check that. Seems to work.
This probably works because Linux x86-64 uses compatibility mode to run the instructions, and the old IA-32 int0x80 system calls work directly on x86-64.
When using external libraries like libc, you also have to take care to link to the right version of the library.
We mostly use int 0x80 system calls here for their simplicity.
However, the best way to do system calls in IA-32 Linux is through sysenter as it is faster. But user applications don't use sysenter directly, but rather VDSO should be used.
The kernel just maps and maintains a magic memory area to every process which contains fast versions of certain functions.
http://stackoverflow.com/questions/19938324/what-are-vdso-and-vsyscall