Where is `scanf` implementation source code?

Question

I want to find C source code for scanf implementation on Linux machine. Googling to find scanf implementation does not tell me the way to find it. I tried to find that source code from gcc source tree using ctags and cscope, but I could not find it. Can anybody please tell me where is scanf function definition, i.e. implementation source code?

Solution

It's in glibc library scanf.c source

glibc stands for GNU C Library. It is a C standard library implementation. It's not a part of the compiler, because you might have different implementations of it (like Microsoft C run-time for example) as well as different compilers (like clang).

Comments

[Alen Milakovic]

You can often obtain this information directly via your distribution. It's easy with Debian/Ubuntu, for example. What is your distribution?

[Markus]

It's Ubuntu 12.04 LTS

[Markus]

Thank you for quick answer! could you please elaborate why that source code is not included(?) in my gcc source tree? I don't know what glibc does(support) for my hello_world program.

[X Tian]

It's the primary library of functions and definitions for C programs. It contains the function you are looking for scanf()

[phk]

Just worth pointing out that other C standard libraries and therefore scanf implementations exist as well, e.g. uClibc: github.com/ffainelli/uClibc/blob/master/libc/stdio/_scanf.c