Revision as of 03:42, 8 February 2007 (view source) osdev>Android Mouse (most of the article taken from parts of the OsFaq)		Revision as of 07:32, 8 February 2007 (view source) Combuster (talk \| contribs) m (fixed links) Newer edit →
Line 11: In addition to standard C functions (as defined in the ISO standard), a C library might (and usually does) implement further functionality, which might or might not be defined by some standard. The standard C library says nothing about networking, for example. For Unix-alike systems, the POSIX standard defines what is expected from a C library; other systems might differ fundamentally. It should be noted that, in order to implement its functionality, the C library must call kernel functions. So, for your own OS, you can of course take a ready-made C library and just recompile it for your OS - but that requires that you tell the library how to call your kernel functions, and your kernel to actually provide those functions. The good news is that [http://sourceware.org/newlib/libc.html#SEC195\| relatively few of the library's functions do use some system call]. Available libraries include the [http://www.gnu.org/software/libc/\| GNU C library] (with info about porting the glibc), [http://sources.redhat.com/newlib/\| newlib] (with info on the required OS functions detailed in the manual), and [http://www.uclibc.org/\| uClibC] (although that is highly optimized to be used with an embedded Linux). It should also be noted that in most cases you can not use a usermode C library directly in your kernel. Things such as malloc, free, memcpy need to implemented by you before being used. In GCC the "--nobuiltin" flag tells GCC to not use pre-existing builtin functions such as memcpy.

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Revision as of 07:32, 8 February 2007