C IODATA     LOGICAL UNITS, POINTERS AND COUNTERS FOR I/O
C
C IECHO      OUTPUT UNIT FOR PRINTING OF INPUT
C ILINE      LINE NUMBER OF INPUT
C ICOL       COLUMN OF INPUT CURRENTLY UNDER EXAMINATION
C IMARK      POSITION OF MARKER FOR ERROR MESSAGE
C NWARN      NUMBER OF WARNING MESSAGES
C NFAIL      NUMBER OF FATAL ERRORS
C IOPER      INDICATOR IF PARAMETER IS ALGEBRAIC EXP.
C
      INTEGER         IECHO, ILINE, ICOL, IMARK, NWARN, NFAIL, IOPER
C
      COMMON /IODATA/ IECHO, ILINE, ICOL, IMARK, NWARN, NFAIL, IOPER