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Re: BLOCK I/O mode in IDL [message #271]

Fri, 06 March 1992 11:22

alans
Messages: 12
Registered: September 1991

Junior Member

In article <28FEB199211431049@stars.gsfc.nasa.gov> thompson@stars.gsfc.nasa.gov (William Thompson, code 682.1, x2040) writes:

> IDL has a handy /BLOCK qualifier for the OPEN* procedures in VAX/VMS, as well
> as the POINT_LUN procedure to set the file pointer to a particular byte. Does
> anybody know what the FORTRAN and/or C equivalents would be for VAX/VMS?

It's been over a year since I've used VMS, so some of this may be outdated or
just plain wrong, but...

VAX FORTRAN:

open (unit=lun, name='whatever', form='unformatted',
& recordtype='fixed', organization='sequential',
& access='direct', et infinitum)
read (unit, recnum, data, etc.)

c (doesn't put you on a byte, but rather a record)

VAX C:
[very hazy on the open here]

fp = fopen ("name", "+rb");
fseek (fp, byte_offset, 0);

Hope it helps a little...
--
Alan J.Stein MIT/Lincoln Laboratory alans@ll.mit.edu

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Re: BLOCK I/O mode in IDL

By: alans on Fri, 06 March 1992 11:22

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