An unallocated variable passed as an argument is not PRESENT

10

@m_b_metcalf , in case this has not been noted already, FIgure A.4 in the Eighth Edition of Modern Fortran Explained has typos related to pivotptr variable since Figure A.3 in indicated as the basis: the following is suggested.

Figure A.4 Huge unreadable nested if constructs

if ( allocated(worka) ) then
   if ( allocated(workb1) then
      if ( allocated(workb2) ) then
         if ( associated(pivotptr) ) then
            call process_work( x, worka, workb1, workbb2, pivotptr )
         else
            call process_work( x, worka, workb1, worbk2 )
         end if
      else if ( associated(pivotptr) ) then
         call process_work( x, worka, workb1, pivot=pivotptr )
      else
         call process_work( x, worka, workb1 )
      end if
.
. ( Remainder of large nested if coonstruct elided
.