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Re: Way to determine big/little endian? [message #26661 is a reply to message #26660]

Wed, 19 September 2001 21:45

Craig Markwardt
Messages: 1869
Registered: November 1996

Senior Member

"Mark Rivers" <rivers@cars.uchicago.edu> writes:

> Is there a built-in way to determine if the machine IDL is running on is
> big-endian or little-endian? I would expect that there might be a field in
> !version, but there is not.
>
> Here is what I am doing to set the Boolean value "big_endian":
>
> ; If this is a big-endian machine swap the byte order
> ; I don't know of a built-in IDL test for endianness, do it ourselves
> t1 = 1
> t2 = 1
> byteorder, t2, /sswap, /swap_if_big_endian
> big_endian = (t1 ne t2)
> if (big_endian) then str = swap_endian(str)
>
>
> Is there a simpler way? It would be nice if swap_endian accepted the
> /swap_if_big_endian and /swap_if_little_endian keywords the way byteorder
> now does.

I use this code when I need to. It's pretty much the same as yours,
but I think mine is just a bit cuter :-).

big_endian = (long(['01'xb,'02'xb,'03'xb,'04'xb],0,1))(0) EQ '01020304'xl

I presume you could make your own SWAP_ENDIAN-like function which
computed this value, and then implemented the /SWAP_IF... keywords.

Cheers,
Craig

--
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Craig B. Markwardt, Ph.D. EMAIL: craigmnet@cow.physics.wisc.edu
Astrophysics, IDL, Finance, Derivatives | Remove "net" for better response
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[Message index]

		Re: Way to determine big/little endian? By: Craig Markwardt on Thu, 20 September 2001 06:38
		Re: Way to determine big/little endian? By: David Fanning on Wed, 19 September 2001 22:02
		Re: Way to determine big/little endian? By: Craig Markwardt on Wed, 19 September 2001 21:45
		Re: Way to determine big/little endian? By: David Fanning on Wed, 19 September 2001 21:36

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