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Fast connection between fortran 77 and 90

  1. Jun 25, 2009 #1

    I'm having kind of a "little" problem. I got an old program written in Fortran77 and I want to implement some functionality from Fortran90 routines. The routines are quite long, so I'm not able to rewrite them in F77...

    Is there a possibility to connect the routines so that they can communicate (exchange variable values) in a fast way.

    I have though about the COMMON Blocks of F77 and the MODULE Statements in F90. Is there a way of connecting these data structures in a way, that a F90 program can read a F77 COMMON Block. (I though about a I/O-interface but I think this is too slow)

    Thanks for your help!
    Last edited: Jun 25, 2009
  2. jcsd
  3. Jun 28, 2009 #2

    The connection between Fortran 77 and Fortran 90 is in my opinion a bit tricky. I have myself succeeded to call Fortran 77 subroutines from Fortran 95 (I assume it works in Fortran 90 also) by using the 'call' statement. I have not succeed to call the Fortran 77 functions but I had to rewrite them as subroutines instead. I don't think it is possible to call Fortran 90 code from Fortran 77. To compile the code I think you need a compiler which is able to compile both Fortran 77 and Fortran 90 code, e.g. gfortran
    I hope this helps
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