[U-Boot] [PATCH] include/compiler.h: remove redunandt declaration of errno

[U-Boot] [PATCH] include/compiler.h: remove redunandt declaration of errno

[y at denx.de]

From: Wolfgang Denk <wd@denx.de>

Commit 37566090 "compiler.h: unify system ifdef cruft here" added both
a "#include <errno.h>" and a "extern int errno;" to include/compiler.h
which is causing build warnings for some systems, for example for the
"netstar" board:

	In file included from /home/wd/git/u-boot/work/lib/crc32.c:15:
	include/compiler.h:28: warning: function declaration isn't a prototype

The declaration of "errno" should be redundant, as <errno.h> is
supposed to provide a correct declaration, so drop it.

Signed-off-by: Wolfgang Denk <wd@denx.de>
Cc: Mike Frysinger <vapier@gentoo.org>
---
 include/compiler.h |    2 --
 1 files changed, 0 insertions(+), 2 deletions(-)

diff --git a/include/compiler.h b/include/compiler.h
index 8030bf6..23f4b83 100644
--- a/include/compiler.h
+++ b/include/compiler.h
@@ -25,8 +25,6 @@
 #include <stdio.h>
 #include <string.h>
 
-extern int errno;
-
 #if !defined(__WIN32__) && !defined(__MINGW32__)
 # include <sys/mman.h>
 #endif
-- 
1.7.0.1

[U-Boot] [PATCH] include/compiler.h: remove redunandt declaration of errno

[Mike Frysinger]

On Saturday, June 19, 2010 20:20:33 y at denx.de wrote:
> Commit 37566090 "compiler.h: unify system ifdef cruft here" added both
> a "#include <errno.h>" and a "extern int errno;" to include/compiler.h

it isnt new code, it sucked the definitions out of random files that had these 
and into one place

> which is causing build warnings for some systems, for example for the
> "netstar" board:
> 
> 	In file included from /home/wd/git/u-boot/work/lib/crc32.c:15:
> 	include/compiler.h:28: warning: function declaration isn't a prototype

never seen that, but i imagine re-ordering the lines might address it as well 
(extern then include)

> The declaration of "errno" should be redundant, as <errno.h> is
> supposed to provide a correct declaration, so drop it.

there are older systems where this isnt true, but ive never used one myself 
and if we dont care about them (i dont), then this is fine
-mike
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[U-Boot] [PATCH] include/compiler.h: remove redunandt declaration of errno

[Wolfgang Denk]

Dear Mike Frysinger,

In message <201006192158.42049.vapier@gentoo.org> you wrote:
>
> On Saturday, June 19, 2010 20:20:33 y at denx.de wrote:
> > Commit 37566090 "compiler.h: unify system ifdef cruft here" added both
> > a "#include <errno.h>" and a "extern int errno;" to include/compiler.h
>
> it isnt new code, it sucked the definitions out of random files that had these 
> and into one place

Yes, I know. I didn't want to blame you, I just wanted to point out
where it's coming from.

> > 	In file included from /home/wd/git/u-boot/work/lib/crc32.c:15:
> > 	include/compiler.h:28: warning: function declaration isn't a prototype
>
> never seen that, but i imagine re-ordering the lines might address it as well 
> (extern then include)
>
> > The declaration of "errno" should be redundant, as <errno.h> is
> > supposed to provide a correct declaration, so drop it.
>
> there are older systems where this isnt true, but ive never used one myself>  
> and if we dont care about them (i dont), then this is fine

Well, the man page says:

        errno is defined by the ISO C standard to be a modifiable
        lvalue of type int, and must not be explicitly declared;
        errno may be a macro. errno is thread-local; setting it in
        one thread does not affect its value in any other thread.

The "must not be explicitly declared" (because it "may be a macro")
is pretty clear, it seems.

Thanks for commenting, I'll apply it then.

Best regards,

Wolfgang Denk

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