/*****************************************************************

                 SUBROUTINE FILEPOS

  FILEPOS FINDS THE PRESENT FILE POINTER POSITION, IN USER
  DESIGNATED UNITS, FROM THE BEGINNING OF THE FILE.  THE UNIT
  FOR A HEADER FILE IS THE SIZE OF STRUCTURE HEADERDATA + THE
  SIZE OF AN INTEGER MULTIPLIED BY THE NUMBER OF PARAMETERS A
  PROBE MEASURES PLUS ONE FOR THE SECOND HEADER AND ONE FOR THE
  DEPTH FOR PROBES WHICH MEASURE MORE THAN ONE PARAMETER.  DATA
  FILES HAVE A UNIT OF SIZE OF INTEGER.  MASK FILES VARY BY THE
  SIZE OF THE STRUCTURE WHICH THEY STORE. 

  NOTE: THIS SUBROUTINE IS NOT PORTABLE TO MACHINES WHERE INTEGER
  AND REAL STORAGE SIZES ARE DIFFERENT.  ON SUCH MACHINES, THIS
  SUBROUTINE CAN ONLY BE USED FOR INTEGER VARIABLES.

******************************************************************/

filepos_(

 int *fn,               /* FILE IDENTIFICATION NUMBER */

 int *head,             /* TYPE OF FILE BEING INVESTIGATED:
                           0 - MASK FILE
                           1 - HEADER FILE
                           2 - NORMAL PARAMETER FILE
                           3 - SPECIAL PARAMETER FILE 
                           4 - .C MASK */

 int *mult,             /* SIZE MULTIPLIER (SEE ABOVE) */

 int *recnum            /* THE RETURNED VALUE, THE PRESENT FILE
                           POINTER POSITION */

         )

{

/****************************************************************

 CALCULATE SIZE OF ONE UNIT (AS DESCRIBED ABOVE).

*****************************************************************/

 off_t size,x;

 if ( *head <= 1 ) 

  size= *head * sizeof( struct headerdata ) + *mult * sizeof( int);

 else if ( *head == 2 )
  
  size= sizeof( struct write2fs );

 else if ( *head == 3 )

  size= sizeof(struct write3fs ); 

 else if ( *head == 4 ) 
  size= sizeof(struct write2c);

/****************************************************************

  CALCULATE FILE POINTER POSITION IN BYTES BY USING FTELL UTILITY.
  DIVIDE BY SIZE TO GET IN PROPER UNITS.

*****************************************************************/

  x=ftello(fp[*fn])/size;
 *recnum = ftello( fp[*fn] )/size;

}