comp.lang.idl-pvwave archive: archive » Re: Fortran unformatted data: Big or little endian

Home » Public Forums » archive » Re: Fortran unformatted data: Big or little endian

Show: Today's Messages :: Show Polls :: Message Navigator
E-mail to friend

Re: Fortran unformatted data: Big or little endian [message #34948 is a reply to message #34947]

Wed, 30 April 2003 13:13

Mark Hadfield
Messages: 783
Registered: May 1995

Senior Member

"Michael Schroeter" <schroeter@muk.uni-hannover.de> wrote in message
news:b8og1i$6bt$1@newsserver.rrzn.uni-hannover.de...

> I have a problem reading Fortran unformatted data in IDL. I have a
> file containing data of well known size (e.g., an array of 100 x 100
> single precision floating point values). Unfortunately, I don't know
> something about the machine (big or little endian machine) on which
> the file has been produced. Is there a way to get this information
> on the fly by IDL in order to open the file automatically in the
> correctly (using the /SWAP_ENDIAN option or not). The way I used so
> far was trial and error. But since I have many of those files I'm
> searching for a solution without recompiling my source code.

If you have a reasonably recent version of IDL (>= 5.4??) and you know
the byte-order of the machine on which you're *reading* the data then
you can use OPEN's SWAP_IF_BIG_ENDIAN or SWAP_IF_LITTLE_ENDIAN
keywords. Here's the documentation entry for the former:

SWAP_IF_BIG_ENDIAN

Setting this keyword is equivalent to setting SWAP_ENDIAN; it only
takes effect if the current system has big endian byte
ordering. This keyword does not refer to the byte ordering of the
input data, but to the computer hardware.

--

Mark Hadfield "Ka puwaha te tai nei, Hoea tatou"
m.hadfield@niwa.co.nz
National Institute for Water and Atmospheric Research (NIWA)

Report message to a moderator

[Message index]

		Re: Fortran unformatted data: Big or little endian By: David Fanning on Sun, 04 May 2003 16:17
		Re: Fortran unformatted data: Big or little endian By: Mark Hadfield on Sun, 04 May 2003 15:07
		Re: Fortran unformatted data: Big or little endian By: David Fanning on Fri, 02 May 2003 16:26
		Re: Fortran unformatted data: Big or little endian By: btt on Fri, 02 May 2003 09:54
		Re: Fortran unformatted data: Big or little endian By: Dick Jackson on Fri, 02 May 2003 09:24
		Re: Fortran unformatted data: Big or little endian By: David Fanning on Wed, 30 April 2003 14:42
		Re: Fortran unformatted data: Big or little endian By: Mark Hadfield on Wed, 30 April 2003 13:52
		Re: Fortran unformatted data: Big or little endian By: David Fanning on Wed, 30 April 2003 13:31
		Re: Fortran unformatted data: Big or little endian By: Mark Hadfield on Wed, 30 April 2003 13:13
		Re: Fortran unformatted data: Big or little endian By: thompson on Wed, 30 April 2003 08:05
		Re: Fortran unformatted data: Big or little endian By: Paul Van Delst[1] on Wed, 30 April 2003 07:48
		Re: Fortran unformatted data: Big or little endian By: David Fanning on Wed, 30 April 2003 06:39
		Re: Fortran unformatted data: Big or little endian By: Michael Schroeter on Wed, 30 April 2003 06:30
		Re: Fortran unformatted data: Big or little endian By: David Fanning on Wed, 30 April 2003 05:55
		Re: Fortran unformatted data: Big or little endian By: Michael Schroeter on Mon, 05 May 2003 02:35
		Re: Fortran unformatted data: Big or little endian By: btt on Mon, 05 May 2003 07:07

Previous Topic:	Fortran unformatted data: Big or little endian
Next Topic:	Re: WIDGET_TEXT - HOW TO NOT CHANGE VALUE OF TEXT WHILE EDITING FIELD?

-=] Back to Top [=-

[ Syndicate this forum (XML) ] [

] [

]

Current Time: Thu Oct 09 21:40:59 PDT 2025

Total time taken to generate the page: 0.80441 seconds