Source code for c / C ++ functions

Question

I wanted to look at the implementation of various C / C ++ functions (e.g. strcpy, stcmp, strstr). This will help me learn good coding techniques in c / C ++. Could you tell me where I can find him?

Thank.

Answer 1

You can check out a glibc copy that will have the source code for all the C functions in the C standard library. This should be a good starting place.

Answer 2

It is worth noting that the source code for the C standard library does not necessarily highlight good coding methods. As a standard library, it has a special status, where, for example, it can rely on many unspecified or non-portable actions simply because they know the exact compiler with which it is used.

And, of course, this only talks about C encoding methods.

This has nothing to do with C ++ coding practice, which is very different. Do not treat them as one language. There is no such thing as C / C ++. C is a language with its own coding methods and common idioms, and C ++ is a separate independent language that also has its own practices and idioms.

Good C code is rarely good C ++ code. strcpy and other C library functions are certainly not good C ++ code.

Answer 3

Many of the standard C library functions have source lists and discussions in the C programming language from Kernighan and Ritchie . Discussions are a useful way to learn more about the specifics of the C language and how functions in the standard library work under the hood.

Answer 4

Most compilers provide source code for the library — however, this source code is usually more complex and confusing than you might expect.

A good resource for this is the PJ Plauger book, "The Standard C Library" , which can be pretty cheap if you go for a used one. The code presented is not always straightforward, but Plauger explains it pretty well (and gives reasons why it may not always be straightforward and still follow the standard).

Answer 5

Look at the implementation of the C libc standard library. To see how the real, popular C library is implemented, take a look at glibc code. You can access the code using git:

git clone git: //sourceware.org/git/glibc.git

As for C ++, you can find the standard glibC ++ library on one of these mirrors:

http://gcc.gnu.org/mirrors.html

You can also check out uLibc, which is likely to be simpler than the GNU library:

http://git.uclibc.org/uClibc/tree/

To give you a taste, here is the strncpy implementation from uLibc:

 Wchar *Wstrcpy(Wchar * __restrict s1, const Wchar * __restrict s2) { register Wchar *s = s1; #ifdef __BCC__ do { *s = *s2++; } while (*s++ != 0); #else while ( (*s++ = *s2++) != 0 ); #endif return s1; } 

Here is strcmp and strstr

Answer 6

c standard library

Answer 7

"Standarc C Library" is a specification. You need sources to implement the specification. Your C compiler may or may not provide such sources - one that does GCC .

Answer 8

You can also view the source OpenBSD tree . In particular, you want a subdirectory of the libc line .

Answer 9

About 10 years ago I read the Plauger Standard C Library . Thoroughly recommend it.

Answer 10

Here you go

The implementation will be slightly different from OS to OS, but the GNU / Linux implementation is likely to be the easiest to find there.

Answer 11

Here are the common strXXX C functions in NetBSD: http://cvsweb.netbsd.org/bsdweb.cgi/src/common/lib/libc/string/

Here's the strXXX NetBSD implementation for i386 processors http://cvsweb.netbsd.org/bsdweb.cgi/src/common/lib/libc/arch/i386/string/

Answer 12

If you are using Visual Studio Professional or Team, you can find the source here:

C: \ Program Files \ Microsoft Visual Studio 9.0 \ VC \ crt \ src

Answer 13

For your purposes, this book may be useful: Master Algorithms with C

Answer 14

In general, I find BSD libc much easier to read than GNU. There is less "gcc-isms", the kernel is much clearer in intentions, etc. For example, the BSD code for malloc is quite readable compared to glibc