How to Write to an Output File

The following example opens an output file and writes selected events to it.

Files for this example

Copy the following files from

/var/phy/project/hep/neutrino/work/schol/superk/examples

• example4.F: contains the source code for the program
• example4.sh: a shell script for running the program
• The GNUmakefile should already have instructions for compiling example4 in it.

Outputting events in ZBS format to a file

Take a look inside example4.F.

• Before the file loop, both input and output files are opened using SKOPENF. SKOPENF is given the argument LUNI (set to the value 10) for the input file, and the argument LUNO (set to the value 20). These are the "logical unit numbers" (luns) associated with the files. These logical unit numbers are associated with the input and output files in the script used to run the program, example4.sh. If you look at this script, you'll see

  10{{"$1",LOCAL,,RED,,,"recl=5670 status=old",}}
  20{{"example4.zbs",LOCAL,,WRT,,,"recl=5670 status=new",}}
  

  The first line in the script here associates "$1" (the filename argument to the script) with lun=10, which is opened first by SKOPENF. The second line associates example4.zbs with the output file lun=20, which is opened next by SKOPENF. You can change the names of input and output ZBS files by changing the filenames in the script.
• For each event with greater than 50 hits in the ID, it writes the event to the output file, using the subroutine KZWRIT:

                 if (nqisk.gt.50) then
                    call kzwrit(luno)
                 endif
  

  This subroutine takes the lun of the file to write to as an argument.
• At the end of the event and file loops, it closes both input and output files with SKCLOSEF.

Compile and run this program in the same way as for the first examples. You should get a file called example4.zbs created. This contains the selected events in ZBS format. You can look at them with superscan, or use this file as input to another SK program.

You can have access to more than one input or output file in the same program, by adding more lines to the script that runs the program, and associating a different lun to each file.