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Re: [PATCH newlib]New configuration option disable io vector buffer in Newlib
- From: Corinna Vinschen <vinschen at redhat dot com>
- To: newlib at sourceware dot org
- Date: Tue, 26 Mar 2013 13:30:48 +0100
- Subject: Re: [PATCH newlib]New configuration option disable io vector buffer in Newlib
- References: <002a01ce2a0a$96b77c90$c42675b0$ at cheng@arm.com>
- Reply-to: newlib at sourceware dot org
On Mar 26 18:13, Bin Cheng wrote:
> Hi,
> Stream IO functions in Newlib construct structures like __suio/__siov, then
> call function __sfvwrite_r to do the buffered IO. From the view of MCU
> programs, this layer code of vector buffer occupies large amount flash and
> is generally unnecessary. So here this patch introduces a new configuration
> time option "--disable-newlib-fvwrite-in-streamio" allowing user to disable
> io vector buffer in Newlib, thus reduces foot-print of stream-io and
> formatted IO.
> The default behavior won't be changed unless the option "--disbale-*" is
> specified explicitly when configuring.
> I tested it with some formatted IO tests and also passed the gcc regression
> test. It has also been applied in the release of "GNU Tools for ARM Embedded
> Processors" and used in many projects I believe.
>
> Is it OK or any suggestions?
Your code looks pretty straightforward to me, so I don't see a reason
not to apply it. Except I don't understand your ChangeLog. What's
the non-existing _FSEEK_OPTIMIZATION having to do with it? Typo?
Corinna
> 2013-03-26 Bin Cheng <...>
> * acconfig.h (_FVWRITE_IN_STREAMIO): Undef
> * newlib.hin (_FVWRITE_IN_STREAMIO): Undef
> * configure.in (--disable-newlib-fvwrite-in-streamio): New option.
> * configure: Regenerated.
> * libc/stdio/fputs.c (_fputs_r): Use _FSEEK_OPTIMIZATION to
> control __sfvwrite_r. Add alternative implementation.
> * libc/stdio/fputws.c (_fputws_r): Ditto.
> * libc/stdio/fwrite.c (_fwrite_r): Ditto.
> * libc/stdio/puts.c (_puts_r): Ditto.
> * libc/stdio/vfprintf.c (__ssputs_r, __sfputs_r): New function.
> (_VFPRINTF_R): Use _FSEEK_OPTIMIZATION to control vector buffer.
> (__SPRINT): Use _FSEEK_OPTIMIZATION to control macro definition.
> * libc/stdio/vfwprintf.c (_VFWPRINTF_R): Use _FSEEK_OPTIMIZATION to
> control vector buffer.
> (__SPRINT): Use _FSEEK_OPTIMIZATION to control macro definition.
Corinna
--
Corinna Vinschen
Cygwin Maintainer
Red Hat