about header files used in score

[Zhongjie]

When you build gcc, you could tell gcc whether you have a c library,
when you tell gcc you do not have
a c library, gcc will define "inhibit_libc", the stdio.h included by
libgcc2.c is in the section with "inhibit_libc"
defined, when you build gcc to *-elf- or *-eabi- , such arm-elf-gcc or
arm-eabi-gcc, you do not need any
c header files for the target.

Regards
Zhongjie
-----Original Message-----
From: Chris Johns <chrisj at rtems.org>
To: Zhongjie <zhurabbit at gmail.com>
Cc: rtems-users at rtems.org
Subject: Re: about header files used in score
Date: Mon, 15 Jun 2009 09:10:59 +1000


Zhongjie wrote:
> thanks for reply.
> I am just beginning studying RTEMS, the newlib depends on a limited 
> number of low level functions.

Welcome.

> In fact, we do not need any C library to build gcc as a cross complier, 
> like arm-elf-gcc, only enable the c
> language. what I concerns is that some part of RTEMS should can be 
> compiled using those compiler.

If you look in libgcc2.c you will see an include for stdio.h. I have always 
needed some libc headers to build gcc.

> Of course, with newlib support, RTEMS works well, it just a little 
> confused logically for a beginner like me.
> as my understanding, it is a c library depends on a os, not a os depends 
> a c library.
> I think we could define those types in rtems, then included by gcc and 
> newlib, but not use those types directly in
> a c library header files. it will make the architecture more clearly.

GCC and newlib have all the types defined for a specific target and RTEMS uses 
them.

Regards
Chris

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