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Message-Id:	<199907162240.RAA20005@mercury.xraylith.wisc.edu>
To:	"Isselmou Ould-Dellahy" <iod AT ccrl DOT mot DOT com>
cc:	cygwin AT sourceware DOT cygnus DOT com
Subject:	Re: unix/MS binary file format
In-Reply-To:	Your message of "Fri, 16 Jul 1999 18:32:40 CDT."
	<19990716183240 DOT A4976 AT diamond DOT ccrl DOT mot DOT com>
Date:	Fri, 16 Jul 1999 17:40:02 -0500
From:	Mumit Khan <khan AT xraylith DOT wisc DOT EDU>

"Isselmou Ould-Dellahy" <iod AT ccrl DOT mot DOT com> writes:
> Hi,
> 
> I would like to create and to be able to read binary files
> on cygwin, such that I can use such files under unix.
> 
> Actually under cygnus the binary files are coded in
> unix reverse order. For example when I put the integer 327656666
> in a binary file (using fwrite) and display it using "od -c"
> I have :
> 
> Unix format :
> 0000000 023 207 244 332
> 0000004
> NT format :
> 0000000 332 244 207 023
> 0000004
> 
> My question is : how can I generate and read unix binary
>                  file format under cygwin ?
> 

It's not an Unix vs Cygwin issue, but rather a "endian-ness" issue,
and hence independent of Cygwin. Little Endian CPUs (eg., x86) will 
store binary data differently by default than Big Endian CPUs (eg., 
SPARC), even when both are running Unix.

Binary files are almost by definition non-portable, but fortunately
that's not the end of the world. There are a variety of libraries 
that will allow you to read/write binary data portably. Please search 
for CDF, HDF, netCDF, XDR. My own code uses a XDR based library that
is customized for our data reader/writer classes.

    HDF         - http://hdf.ncsa.uiuc.edu/
    NetCDF      - http://www.unidata.ucar.edu/
    CDF         - http://nssdc.gsfc.nasa.gov/cdf
    XDR         - Sun's documentation (http://docs.sun.com/)


My preference for general-purpose work is NetCDF, but the others
are just as good. Most of these will build out of the box (and
others have done the port -- check the archives) on Cygwin with
minor configuration tweaks.

Regards,
Mumit


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