[petsc-users] KSP in common blocks

[Sanjay Govindjee]

In upgrading to PETSc v3.8.x, we are seeing a compilation error with 
gfortran (version 6.2.0, users report the same problem with version 
7.x).   The compile error is thrown when, say, type KSP variables are 
put in common blocks; we do not see any errors with this construct
when using ifort (Intel compiler version 14.0.3).

The compile error is easily reproduced.  For example in 
src/ksp/ksp/examples/tutorials, below the line

     KSP ksp

just add the line

     common /mycom/ ksp

gfortran then complains with:

        KSP             ksp
                                 1
Error: Derived type variable ‘ksp’ in COMMON at (1) has neither the 
SEQUENCE nor the BIND(C) attribute

ifort is perfectly happy and produces executable code.  Any ideas on how 
to fix this problem?

-sanjay