[fitsbits] How to do a row filter

[Patrick L. Nolan]

I have a C program that reads big FITS files.  It works, but now
I'm trying to see if a row filter would improve performance.
Apparently I haven't yet understood the proper syntax for a
row filter.

It opens a file with a name like this:
  day001.fits[LAT_Event_Summary][Ph_L > 64. && Ph_L < 95.]
It fails with error #302, "column number < 1 or > tfields".

Here's what I know:
* The program works OK if I open file "day001.fits" without
the filter.

* The first extension is a binary table with
EXTNAME = 'LAT_Event_Summary'  /

* This table has a column like this:
TTYPE3  = 'Ph_L    '           /Galactic Longitude                              
TFORM3  = 'E       '           /                                                
TUNIT3  = 'deg     '           / 

* TFIELDS = 6 for this table.

OK.  Fire away.  What did I miss?

-- 
*   Patrick L. Nolan                                          *
*   W. W. Hansen Experimental Physics Laboratory (HEPL)       * 
*   Stanford University                                       *