R help - Feb 2012 - Using readBin to read binary "unformatted" output files from Fortran?

Hello, 

I'm wondering if I can get some help with reading Fortran binary
"unformatted" output files into R.

The Fortran output files were generated in Ubuntu 10.04 LTS using gfortran4.4,
on a 32bit Intel Core 2 Duo 3.16 GHz machine, with little-endian and record
marker lengths equal to 4.

The machine I'm currently trying to read this Fortran output file is a
Macbook Pro running Lion 10.7.3, on a 2.26 GHz Intel Core 2 Duo with 4Gb of ram.
I'm running R 2.14.1.

Based on whatever information I could gather from the web, I've been trying
out the following code (the name of the Fortran output file is
"header", located in the current working directory).
> to.read <- file("header", "rb")
> readBin(to.read, "integer", n=2, size = 4, endian =
"little")
Unfortunately, these commands return empty.

Am I on the right track here? Is what I'm trying to accomplish here even
technically possible?

Any help would be greatly appreciated.

Thanks in advance,

Jooil

-- 
Jooil Kim
Postdoc Fellow
Scripps Institution of Oceanography, UC San Diego
Mailing address:
9500 Gilman Drive # 0244
La Jolla, CA 92093-0244, USA
For FedEx/UPS:
8675 Discovery Way, Vaughan Hall Rm. 447
La Jolla, CA 92037, USA



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On 12-02-14 10:58 PM, Jooil Kim wrote:
> Hello,
>
> I'm wondering if I can get some help with reading Fortran binary
"unformatted" output files into R.
>
> The Fortran output files were generated in Ubuntu 10.04 LTS using
gfortran4.4, on a 32bit Intel Core 2 Duo 3.16 GHz machine, with little-endian
and record marker lengths equal to 4.
>
> The machine I'm currently trying to read this Fortran output file is a
Macbook Pro running Lion 10.7.3, on a 2.26 GHz Intel Core 2 Duo with 4Gb of ram.
I'm running R 2.14.1.
>
> Based on whatever information I could gather from the web, I've been
trying out the following code (the name of the Fortran output file is
"header", located in the current working directory).
>
>> to.read<- file("header", "rb")
>> readBin(to.read, "integer", n=2, size = 4, endian =
"little")
>
> Unfortunately, these commands return empty.
>
> Am I on the right track here? Is what I'm trying to accomplish here
even technically possible?
Yes, that should have worked.  To debug, I'd replace your second line with

readBin(to.read, "raw", n=100)

For example, when I create a file by writing out 1:10 using writeBin, 
that gives

 > readBin(to.read, "raw", n=100)
  [1] 01 00 00 00 02 00 00 00 03 00 00 00 04 00 00 00 05 00 00
[20] 00 06 00 00 00 07 00 00 00 08 00 00 00 09 00 00 00 0a 00
[39] 00 00

from which it is pretty obvious the file contains small integers in 
little endian form.  Paul Murrell's hexView package gives more elaborate 
possibilities.

Duncan Murdoch