FORTRAN 64Bit Project

[Alemdar__Bulent]

Hello

I have been working on porting several 32bit projects to 64bit platform. Tthe main program is a C\C++ project and it calls  Fortran functions (similarly, some of Fortran functions call C\C++ functions as well).  Projects compile and link juts fine for 32x.  Once, I change it to  it to 64x, I am getting lots of unresolved external symbol errors like this one

1>Interface_Linear_Direct_Integration_X.obj : error LNK2019: unresolved external symbol Print_decomp_message referenced in function "void __cdecl monitorf(class AG_SparseSymMatrix *,void *)" (?monitorf@@YAXPEAVAG_SparseSymMatrix@@PEAX@Z)

1>Interface_X.obj : error LNK2001: unresolved external symbol Print_decomp_message

And, the Fortran function "Print_decomp_message" is defined like this:

 SUBROUTINE Print_decomp_message(IMSG,NEQN,DIAG_NEW,DIAG_OLD)
 !MS$ATTRIBUTES c,alias: '_Print_decomp_message'::Print_decomp_message  

I am using MS VS2013 and Intel Fortran (Parallel Studio XE 2015 Composer Edition, for Fortran Windows). I am guessing that this problem is somehow related to function name decorating (mangling) but I could not figure it out yet. 

I am not quite familiar with Fortran language so any help, suggestion, or reference to some materials documents are greatly appreciated. 

Regards

Bulent

[TimP]

Apparently, the specification of a leading underscore has broken x64 compatibility. This isn't standard Fortran. The Fortran standard way with iso c binding and no explicit underscore should be compatible with both 32 and 64 bit mode

[Lorri_M_Intel · Accepted solution]

While using the standard iso_c_binding mechanisms would be *best*, this is the quickest solution to get you going.

change this:

 !MS$ATTRIBUTES c,alias: '_Print_decomp_message'::Print_decomp_message 

to this:

 !MS$ATTRIBUTES c,alias: 'Print_decomp_message', decorate ::Print_decomp_message 

              --Lorri

[Alemdar__Bulent]

Lorri

Thanks a lot. this solution fixed my problem.

Regards

Bulent