问题
I'm working on some scientific code that is mostly F77 but also some F95. In places, I need to include F77 code into my F95 code. Is there a way to get this code to play nicely within my code by using a particular compiler flag or something? I'm using gfortran and occasionally ifort. It is possible for me to modify the legacy code but I would need to do it in a sensible way to maintain backwards compatibility with other F77 code while also being forwards compatible with F95 code.
I get errors like:
cstruc:16.12:
Included at mod_op.f90:6:
REAL*8
1
Error: Invalid character in name at (1)
cstruc:17.6:
Included at mod_op.f90:6:
& RH, RH1, ! ln rho
1
Error: Invalid character in name at (1)
cstruc:18.6:
Included at mod_op.f90:6:
& RHP, RHP1, ! d ln rho / d ln p
1
Error: Invalid character in name at (1)
cstruc:19.6:
Included at mod_op.f90:6:
& RHT, RHT1, ! d ln rho / d ln T
1
Error: Invalid character in name at (1)
cstruc looks like this:
REAL*8
& RH, RH1, ! ln rho
& RHP, RHP1, ! d ln rho / d ln p
& RHT, RHT1, ! d ln rho / d ln T
& PSI, ! ln Lambda (for degenerate gas)
& RHPSI, ! d ln rho / d PSI
& RHPSIP, ! d2 ln rho / d PSI d ln P
& RHPSIT, ! d2 ln rho / d PSI d ln T
& PL, ! P at J1
& TONI ! T at J1
Any help is much appreciated. Thanks!
回答1:
With some exceptions, Fortran 77 code is Fortran 95 code. I guess that your errors come from that you are attempting to include fixed-form source code (your F77 code in cstruc) into a free-form source code file mod_op.f90. This is unlikely to end well.
Most compilers will assume a file ending in ".f90" is free-form, so if you really are using fixed-form then you will need a compiler flag to override the assumption.
It is possible to combine free- and fixed-form code into a final object (each compiled separately), but a good suggestion as to how to resolve the problems you are seeing can come only with more detail.
However, if you are attempting with your include to create a module to replace a common block, then there is no reason why you can't use the F95 feature with fixed-form. Just do that selectively.
Alternatively, you can see the answer by Vladimir F which explains how to write source code that is valid as both free-form and fixed-form source. You can use this to modify the Fortran 77 fixed-form code to be include-able by the Fortran 90 free-form code while still being compilable as fixed-form (but not valid Fortran 77).
回答2:
I suggest to try the "intersection" form from http://fortranwiki.org/fortran/show/Continuation+lines
It is legal as both free and fixed source form.
来源：https://stackoverflow.com/questions/22048719/combining-f77-and-f95-fortran-code