Preprocessing issue with VS

[Yaqi_Wang]

To demonstrate this issue, I created three files.

The first 'dim.h' is a one-line header file with a variable definition in it:

#define dim 2

The second file 'typ_boundary.f90' contains a module definition:

#include "dim.h"
#if (dim==2)
MODULE TypBoundary_2D
#elif (dim==3)
MODULE TypBoundary_3D
#endif

INTEGER, PARAMETER :: vacuum_bc =-1
INTEGER, PARAMETER :: reflecting_bc =-2
INTEGER, PARAMETER :: MaxNonHom_bc =-10
INTEGER, PARAMETER :: MinNonHom_bc =-99

! boundary types
INTEGER, PARAMETER, PRIVATE :: num_bdry_types = 2

INTEGER, PARAMETER :: vacuum = 1
INTEGER, PARAMETER :: reflecting = 2

CONTAINS

FUNCTION boundary_type(boundary_indicator)
IMPLICIT NONE
INTEGER :: boundary_indicator, boundary_type
SELECT CASE (boundary_indicator)
CASE (vacuum_bc, MinNonHom_bc:MaxNonHom_bc)
boundary_type = vacuum
CASE (reflecting_bc)
boundary_type = reflecting
CASE DEFAULT
stop 'wrong indicator'
END SELECT
RETURN
END FUNCTION boundary_type

LOGICAL FUNCTION is_boundary(boundary_indicator)
IMPLICIT NONE
INTEGER :: boundary_indicator
SELECT CASE (boundary_indicator)
CASE (vacuum_bc, MinNonHom_bc:MaxNonHom_bc, reflecting_bc)
is_boundary = .true.
CASE DEFAULT
is_boundary = .false.
END SELECT
RETURN
END FUNCTION is_boundary

INTEGER FUNCTION num_boundary_type()
IMPLICIT NONE
num_boundary_type = num_bdry_types + 1
RETURN
END FUNCTION num_boundary_type

INTEGER FUNCTION periodic_type()
IMPLICIT NONE
periodic_type = num_boundary_type()
RETURN
END FUNCTION periodic_type

#if (dim==2)
END MODULE TypBoundary_2D
#elif (dim==3)
END MODULE TypBoundary_3D
#endif

The last file 'Source1.f90' is the main:

#include "dim.h"
program test
#if (dim==2)
USE TypBoundary_2D
#elif (dim==3)
USE TypBoundary_3D
#endif
implicit none

print *, num_boundary_type()

stop
end program test

We can compile these three files with Visual Studio+Intel Visual
Fortran by turning fpp (fortran preprocess for all derivatives) on and
adding the directory where dim.h is in into the including directory.
I am using Intel Visual Fortran Compiler Integration for Microsoft
Visual Studio* 2008, 11.1.3471.2008.
The problem is that Visual Studio always do the rebuild even nothing
is changed after the last build.

I also create a simple makefile with gfortran in cygwin:

testpre : typ_boundary.o Source1.o
gfortran -o testpre typ_boundary.o Source1.o

typ_boundary.o : typ_boundary.f90 dim.h
gfortran -c -cpp -I. typ_boundary.f90

Source1.o : Source1.f90 dim.h typ_boundary.o
gfortran -c -cpp -I. Source1.f90

It just works fine.

So it must be the preprocessing derivatives that cause VS always do
the rebuild. Is this a bug in VS or something I misunderstand?

Thanks.

[Yaqi_Wang]

found an easy solution:

instead using,

#if (dim==2)
MODULE TypBoundary_2D
#elif (dim==3)
MODULE TypBoundary_3D
#endif

use,

MODULE &

#if (dim==2)
TypBoundary_2D
#elif (dim==3)
TypBoundary_3D
#endif

[Yaqi_Wang]

Apparently, module keyword and the module name must be on the same line so that VS can create correct dependencies.

So the solution in my previous post is incorrect.

[jimdempseyatthecove]

Try:


#if (dim==2)
#define TypBoundary_nD TypBoundary_2D
#elif (dim==3)
#define TypBoundary_nD TypBoundary_3D
#else
#error error in dim
#endif

MODULE TypBoundary_nD

Jim Dempsey

[Yaqi_Wang]

VS still do the rebuild every time.

But this does help on cleaning up my code. Thanks.

[jimdempseyatthecove]

Try placing your modules into a seperate project (static library)from the program/subroutines/functions.

Note, if possible, have the module library contain all the varients of the modules xxx_2D, xxx_3D, ...

The output of the module library project will be

YourModuleLibrary.lib
plus
xxx_2D.MOD
xxx_3D.MOD
...

Make the program/subroutines/functions project dependent on the modules project. (and set build order accordingly)

These projects can all be in the same solution.

Jim Dempsey