I'm just getting started with CGo and I'm trying to send data to a C library that performs statistical computations on arrays of floats/doubles. What I'm trying to figure out right now is how to send an array of floats, or C.double's, to a CGo function that has a signature like this:
double pop_mean(int numPoints, double a[])
I've figured out how to get in the C.int in there, but I'm having trouble figuring out how to send in an array of doubles.
I haven't yet seen any blog posts or SO Questions about this exact thing, so I thought I'd ask.
The following is my best effort so far.
// Get a basic function to work, while passing in an ARRAY arr := make([]C.double, 0)
arr = append(arr, C.double(10.0))
arr = append(arr, C.double(20.0))
arr = append(arr, C.double(30.0))
var fixedArray [3]C.double = arr[:]
// ptr := C.CBytes(arr)
// defer C.free(unsafe.Pointer(ptr))
coolMean := C.pop_mean(3, &fixedArray)
fmt.Println("pop_mean (10, 20, 30): ", coolMean)
And this is the error I'm getting:
./main.go:64:6: cannot use arr[:] (type []_Ctype_double) as type [3]_Ctype_double in assignment
./main.go:69:35: cannot use &fixedArray (type *[3]_Ctype_double) as type *_Ctype_double in argument to _Cfunc_pop_mean
How should I be passing an array of C.double to the code?