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Re: OPENR F77 SWAP_IF_LITTLE_ENDIAN [message #90725 is a reply to message #90724]

Mon, 06 April 2015 12:43

Lajos Foldy
Messages: 176
Registered: December 2011

Senior Member

On Monday, April 6, 2015 at 8:04:05 PM UTC+2, Edward Hyer wrote:
> ; open and write a file using F77_UNFORMATTED
> IDL> openw,lun,/get_lun,/f77,'/tmp/test_f77'
> IDL> writeu,lun,long(2015032518),float(6),long(0)
> IDL> free_lun,lun
> ; read the file back in
> IDL> openr,lun,/get_lun,/f77,'/tmp/test_conc'
> IDL> qq1=long(0) & qq2=float(0) & qq3=long(0)
> IDL> readu,lun,qq1,qq2,qq3
> IDL> print,qq1,qq2,qq3
> 2013052306 6.00000 0
> IDL> free_lun,lun
> ; now try reading it with /SWAP_IF_LITTLE_ENDIAN
> IDL> openr,lun,/get_lun,/f77,'/tmp/test_conc',/swap_if_little_end ian
> IDL> readu,lun,qq1,qq2,qq3
> % READU: Corrupted f77 unformatted file detected. Unit: 100
> File: /tmp/test_conc
> % Execution halted at: $MAIN$
>
>
> Has anyone encountered this behavior?
>
> --Edward H.

F77 unformatted files contain record length data. Byte swapping them will result in corrupted records.

regards,
Lajos

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[Message index]

		OPENR F77 SWAP_IF_LITTLE_ENDIAN By: MarioIncandenza on Mon, 06 April 2015 11:04
		Re: OPENR F77 SWAP_IF_LITTLE_ENDIAN By: Lajos Foldy on Mon, 06 April 2015 12:43
		Re: OPENR F77 SWAP_IF_LITTLE_ENDIAN By: Paul Van Delst[1] on Mon, 06 April 2015 13:00
		Re: OPENR F77 SWAP_IF_LITTLE_ENDIAN By: Paul Van Delst[1] on Mon, 06 April 2015 12:45
		Re: OPENR F77 SWAP_IF_LITTLE_ENDIAN By: MarioIncandenza on Mon, 06 April 2015 17:27

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