c++ - How to split class definition between multiple .cpp and .cu files? -

i've got class nested classes mixing both c++, cuda , thrust. want split member definitions across number of files.

// in cls.h: #include <thrust/device_vector.h> class cls {     class foo {   // define in foo.cu    (include "cls.h")         kernelwrapper();     }     class bar {   // define in bar.cu    (include "cls.h")         thrust::device_vector a;         thruststuff();     }     thrust::device_vector b;     purecpp();      // define in cls.cpp (include "cls.h")     morethrust();   // define in cls.cu  (include "cls.h") } 

in each definition file #include "cls.h". however, getting assortment of compiler errors no matter try, purecpp referenced not defined.

• i've read thrust can used .cu files. because parent class cls declares thrust-type variables b (and hence #includes thrust/device_vector.h), force files #include cls.h made .cu files?

• where use extern "c" in case? suppose cls.cpp require functions in .cu files wrapped in extern "c", .cu .cu calls, morethrust() calling bar::thruststuff()

• i've been made aware members of classes don't work extern "c", have write extern "c" wrapper function each member function?

i'm utterly confused how make work - cocktail of #includes , extern "c"s need each file?

taking small example, compiled , ran fine me

/* inside file cls.h */ #pragma once #include <thrust/device_vector.h> #include <stdio.h>  class cls {  public:     class foo {   // define in foo.cu    (include "cls.h")     public:         void kernelwrapper();     };      class bar {   // define in bar.cu    (include "cls.h")         thrust::device_vector<int> a;     public:         void thruststuff();     };  public:     void purecpp();      // define in cls.cpp (include "cls.h")     void morethrust();   // define in cls.cu  (include "cls.h")  private:     thrust::device_vector<int> b; };  /* inside file foo.cu */ #include "cls.h" void cls::foo::kernelwrapper() {     printf("kernelwrapper\n"); }  /* inside file bar.cu */ #include "cls.h" void cls::bar::thruststuff() {     printf("thrust stuff\n"); }  /* inside file cls.cpp */ #include "cls.h" void cls::purecpp() {     printf("purecpp\n"); }  /* inside file cls.cu */ #include "cls.h" void cls::morethrust() {     printf("morethrust\n"); }   /* inside file main.cpp */ #include "cls.h" int main() {     cls a_class;     a_class.purecpp();     a_class.morethrust();      cls::bar a_class_bar;     a_class_bar.thruststuff();      cls::foo a_class_foo;     a_class_foo.kernelwrapper(); } 

running prints

purecpp

morethrust

thrust stuff

kernelwrapper

if anything, i'd bet you're using ide , it's not compilling of files, while have class member declaration in header file, it'll never find corresponding definition. exact compilation commands different, me (on linux) used

nvcc -g -g -o0 -gencode arch=compute_20,code=sm_21 -odir "src" -m -o "src/bar.d" "../src/bar.cu" nvcc --device-c -g -o0 -g -gencode arch=compute_20,code=sm_21  -x cu -o  "src/bar.o" "../src/bar.cu"  nvcc -g -g -o0 -gencode arch=compute_20,code=sm_21 -odir "src" -m -o "src/cls.d" "../src/cls.cu" nvcc --device-c -g -o0 -g -gencode arch=compute_20,code=sm_21  -x cu -o  "src/cls.o" "../src/cls.cu"  nvcc -g -g -o0 -gencode arch=compute_20,code=sm_21 -odir "src" -m -o "src/foo.d" "../src/foo.cu" nvcc --device-c -g -o0 -g -gencode arch=compute_20,code=sm_21  -x cu -o  "src/foo.o" "../src/foo.cu"  nvcc -g -g -o0 -gencode arch=compute_20,code=sm_21 -odir "src" -m -o "src/main.d" "../src/main.cpp" nvcc -g -g -o0 --compile  -x c++ -o  "src/main.o" "../src/main.cpp"  nvcc -g -g -o0 -gencode arch=compute_20,code=sm_21 -odir "src" -m -o "src/clscpp.d" "../src/cls.cpp" nvcc -g -g -o0 --compile  -x c++ -o  "src/clscpp.o" "../src/cls.cpp"  nvcc --relocatable-device-code=true -gencode arch=compute_20,code=sm_21 -link -o  "split_compilation"  ./src/bar.o ./src/cls.o ./src/foo.o ./src/clscpp.o ./src/main.o    

the idea compile of source files , link them together. example, if didn't compile , link cls.cpp file, i'd linker error on calls purecpp.

also, note if you're using actual device code, you'll have have specify __device__ and/or __host__ member functions. see this other question