dongyou6795
dongyou6795
2018-11-18 02:02
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已采纳

从go调用fortran库的最小示例

I am looking for a minimal example of the FFI between these two languages, a very simple hello world of a Go program calling a Fortran library.

I want to emphasize I am not looking for external resources, recommendations, or a tutorial, only a minimal code snippet in golang, and the corresponding format in Fortran.

There are plenty of examples on this site of:

A Go -> Fortran example would be in line with these and useful for other developers.

Edit to address duplication claim

This question has an answer and the one linked to as this being a duplicate of does not. Closing and redirecting this question as a duplicate that is likely to be closed with -5 votes would not be useful to stackoverflow users, though both present a reasonable question.

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1条回答 默认 最新

  • doudou3935
    doudou3935 2018-11-18 12:03
    已采纳

    cgo (https://golang.org/cmd/cgo/) seems to provide a functionality for calling C. So I've tried using it for calling Fortran (with go-1.11 + gfortran-8.2 on OSX10.11), which seems to be working for this simple program...

    main.go:

    package main
    
    // #cgo LDFLAGS: mylib.o -L/usr/local/Cellar/gcc/8.2.0/lib/gcc/8 -lgfortran
    // void hello();
    // int  fort_mult( int );
    // void array_test1 ( double*, int* );
    // void array_test2_( double*, int* );
    import "C"
    import "fmt"
    
    func main() {
        // print a message
        C.hello()
    
        // pass a value
        fmt.Println( "val = ", C.fort_mult( 10 ) )
    
        k := C.int( 777 )
        fmt.Println( "val = ", C.fort_mult( k ) )
    
        // pass an array
        a := []C.double {1, 2, 3, 4, 5.5555}
        n := C.int( len(a) )
    
        C.array_test1( &a[0], &n )  // pass addresses
        fmt.Println( a )
    
        C.array_test2_( &a[0], &n )  // no use of iso_c_binding
        fmt.Println( a )
    }
    

    mylib.f90:

    subroutine hello() bind(C)
        print *, "Hello from Fortran"
    end subroutine
    
    function mult( x ) result( y ) bind(C,name="fort_mult")  ! can use a different name
        use iso_c_binding, only: c_int
        integer(c_int), value :: x
        integer(c_int) :: y
    
        y = x * 10
    end function
    
    subroutine array_test1( arr, n ) bind(C)   ! use iso_c_binding
        use iso_c_binding, only: c_int, c_double
        integer(c_int) :: n
        real(c_double) :: arr( n )
    
        arr(:) = arr(:) * 100.0d0
    end subroutine
    
    subroutine array_test2( arr, n ) ! no use of iso_c_binding (e.g. for legacy codes)
        integer :: n
        double precision :: arr( n )   ! or real(8) etc
    
        arr(:) = arr(:) * 2.0d0
    end subroutine
    

    Compile:

    gfortran -c mylib.f90
    go build main.go
    ./main
    

    Result:

     Hello from Fortran
    val =  100
    val =  7770
    [100 200 300 400 555.5500000000001]
    [200 400 600 800 1111.1000000000001]
    
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