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

                 SUBROUTINE READMASK4

 READMASK4 READS A FOUR INTEGER STRUCTURE FROM A FILE.

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

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

 MAKE IR4 A WRITE4 STRUCTURE (FOUR INTEGERS).  THE FIRST INTEGER
 IS IR3.NUM, THE SECOND IS IR3.NUM2, THE THIRD IS IR3.REC,
 THE FOURTH IS IR3.GEO

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

struct write4 ir04;

readmask4_(

 int *jj,              /* PROFILE HEADER RECORD NUMBER */

 int *fn,              /* MASK FILE IDENTIFICATION NUMBER */

 int *iend,            /* SET TO ONE IF END OF FILE IS REACHED */
 
 int *isecond,         /* SECOND INTEGER READ IN */

 int *ithird,          /* THIRD INTEGER READ IN */

 int *ifour           /* FOURTH INTEGER READ IN */

          )

{

 if ( !feof(fp[*fn])) {

   fread( &ir04, sizeof( struct write4 ), 1, fp[*fn] );
   *jj = ir04.num;
   *isecond = ir04.num2;
   *ithird = ir04.rec;
   *ifour = ir04.geo;

 }

 if ( feof(fp[*fn])) *iend = 1;

}