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GNU Info (fftw.info)Calling FFTW from FortranCalling FFTW from Fortran ************************* The standard FFTW libraries include special wrapper functions that allow Fortran programs to call FFTW subroutines. This chapter describes how those functions may be employed to use FFTW from Fortran. We assume here that the reader is already familiar with the usage of FFTW in C, as described elsewhere in this manual. In general, it is not possible to call C functions directly from Fortran, due to Fortran's inability to pass arguments by value and also because Fortran compilers typically expect identifiers to be mangled somehow for linking. However, if C functions are written in a special way, they *are* callable from Fortran, and we have employed this technique to create Fortran-callable "wrapper" functions around the main FFTW routines. These wrapper functions are included in the FFTW libraries by default, unless a Fortran compiler isn't found on your system or `--disable-fortran' is included in the `configure' flags. As a result, calling FFTW from Fortran requires little more than appending ``_f77'' to the function names and then linking normally with the FFTW libraries. There are a few wrinkles, however, as we shall discuss below. automatically generated by info2www version 1.2.2.9 |