Re: read() MAX_IO_SIZE bytes, more than SSIZE_MAX?

From: Joachim Schmitz <jojo@schmitz-digital.de>
Date: Feb 7, 2015, 17:29 UTC
Message-ID: <loom.20150207T182443-33@post.gmane.org>
In-Reply-To: <54D64939.4080102@web.de>

Torsten Bögershausen <tboegi <at> web.de> writes:

> 
> On 2015-02-07 17.45, Joachim Schmitz wrote:

<snip>

Show 13 quoted lines

> 
> How about changing wrapper.c like this:
> 
> #ifndef MAX_IO_SIZE
>  #define MAX_IO_SIZE (8*1024*1024)
> #endif
> ---------------------
> and to change config.mak.uname like this:
> 
> ifeq ($(uname_S),NONSTOP_KERNEL)
> 
> 	BASIC_CFLAGS += -DMAX_IO_SIZE=(32*1024)
> Does this work for you ?

Of course it would, but, a) 32k is smaller than we can go (and yes, we could make it 52k) b) never ever should read() be asked to read more than SSIZE_MAX, this should be true for every platform on the planet? You may want to have is smaller than SSIZE_MAX (like the current 8MB vs. the possible 2TB on Linux), but surely never larger?

Bye, Jojo