Diagnostics for FZLOC

CALL FZLOC (LUN,IOMODE)

This routine is called from the FZ routines to access the control information for the needed stream. FZLOC checks whether the access is legal.

#ZFATAL>ZFATAL termination

  case 1 :  WRITE after READ without switching by FZENDI
  case 2 :  READ after WRITE without switching by FZENDO
  case 3 :  access permission fault, for example : trying to
            write to a file which is open for input only
  case 4 :  access to a file not declared with FZFILE

the following numbers are given in /QUEST/IQUEST(100)

for cases 1 to 4 :

 IQUEST(11) = LUN, the logical unit number
 IQUEST(12) = I/O mode :   1 : needed for input
                           2 : needed for output

for cases 1 to 2 :

 IQUEST(13) = last activity on this file
              (cf. FZ control-bank decription in book FZ)

      =  0  file unused             10  switch input to output
         1  read start-of-run       11  write start-of-run
         2  read d/s                12  write d/s
         3  read end-of-run         13  write d/s, buffer flushed
         4  read Zebra EoF          14  write end-of-run
         5  read system EoF         15  write end-of-file
         6  read end-of-data        16  write end-of-data
         7  attempted read          17  attempted write beyond EoD
         8  rewind after read       18  rewind after write

for case 3 :

 IQUEST(13) = ready for  input :  1 or 3
                        output :  2 or 3