# Fortran Wiki SEQUENCE types allowed for extensions

The follwing code does not work, as it is not conforming to the standard:

TYPE CQUAD                  ! 200/00  QuadElements
SEQUENCE
INTEGER   NR             !  elementnumber
INTEGER   NODE(4)        !  nodenumbers
INTEGER   MAT            !  materialnumber
REAL*4    DET(0:2)       !  Parameter of Jacobi Determinant
REAL*4    THICK(0:4)     !  element thickness
REAL*4    T(3,3)         !  transformation matrix

INTEGER, POINTER :: SGRP(:)    ! OPTIONAL LIST OF SECONDARY GROUPS

END

The SEQUENCE or a BIND is required to allow passing the structure to a C-Program. I can not see any reason for the restrictions not to allow those types to be extended. (A Sequence type should not contain pointers etc, that is evident)

One solution to this problem is to use the UNION / MAP statements available in /DEC/IBM/INTEL Compilers, but they are not part of the standard.