compiling multiple cuda files

[YoshikawaMasashi]

I'm trying to compile multiple Cuda files that have dependencies. and I got an error message.
Is there a way to compile multiple CUDA files using cc-rs?

build.rs

extern crate cc;

fn main() {
    cc::Build::new()
        .cuda(true)
        .flag("-gencode")
        .flag("arch=compute_60,code=sm_60")
        .flag("-gencode")
        .flag("arch=compute_61,code=sm_61")
        .flag("-gencode")
        .flag("arch=compute_62,code=sm_62")
        .file("cuda_src/a.cu")
        .file("cuda_src/b.cu")
        .compile("kernel.o");

    println!("cargo:rustc-link-search=native=/usr/local/cuda/lib64");
    println!("cargo:rustc-link-lib=cudart");
}

a.cu

#include "b.h"

__device__ int a_func(int x) {
    return b_func(x) + 1;
}

b.cu

#include "b.h"

__device__ int b_func(int x) {
    return x + 1;
}

b.h

__device__ int b_func(int x);

error

warning: ptxas fatal   : Unresolved extern function '_Z6b_funci'
error: failed to run custom build command for `cc-rs-test v0.1.0

[alexcrichton]

Sorry I do not know anything about cuda, so I am not able to help you here.