From help-octave-request at bevo dot che dot wisc dot edu Wed Jan 21 22:31:39 2004
Subject: Re: Testing endianness
From: Paul Kienzle <pkienzle at users dot sourceforge dot net>
To: Octave_post <help-octave at bevo dot che dot wisc dot edu>
Date: Wed, 21 Jan 2004 23:30:06 -0500


On Jan 21, 2004, at 4:38 PM, John W. Eaton wrote:

> On 16-Jan-2004, Paul Kienzle <pkienzle at users dot sourceforge dot net> wrote:
>
> | Do I need to test both conditions as in the following:
> |
> |      if octave_config_info("words_little_endian")
> | 	do little endian stuff
> |      elseif octave_config_info("words_big_endian")
> | 	do big endian stuff
> |      else
> | 	error("not little endian or big endian")
> |      endif
>
> Right, I wasn't sure what to do.  We have both words_big_endian and
> words_little_endian in C++, so I just put both in octave_config_info.
> If neither are true, I imagine it is a bug.  Would it be better to
> have a different single value stored in octave_config_info?  If so,
> what would you like to call it?

In suggesting a workaround for M. Cardoso, I
chose only one of them:

# untested code
function r=is_big_endian
static big=[];
if isempty(big)
  [fid,msg] = tmpfile();
  if (fid < 0) error("%s",msg); end
  fwrite(fid, 1, 'long');
  frewind(fid);
  big = fread(fid,1,'char')!=1
  fclose(fid);
endif
r = big

It is easy enough to query is_big_endian or !is_big_endian
depending on need.

Paul Kienzle
pkienzle at users dot sf dot net



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