For more information, read this [nVidia forum](https://devtalk.nvidia.com/default/topic/1022648/cuda-setup-and-installation/cuda-9-unsupported-visual-studio-version-error/4)
There were name conflicts between the 3 `Backend` classes that confused the compiler:
> template instantiation resulted in unexpected function type of "type" (the meaning of a name may have changed since the template declaration -- the type of the template is "type")
.
I renamed the CPU and GPU as `cpuBackend` and `gpuBackend`.
5.__Fix error : identifier "CUDA_FLT_MAX" is undefined in device code__
`CUDA_FLT_MAX` is not seen from the device and I had to declare it as `__constant__`.
From [StackOverflow](https://stackoverflow.com/questions/20111409/how-to-pass-structures-into-cuda-device#comment29972423_20112013):
> Undecorated constants get compiled into both host and device code with gcc based toolchains, but not with the Microsoft compiler.
6.__Fix fatal error C1019: unexpected #else__
There was preprocessor instructions (`#ifdef ... #else ... #endif`) in the middle of a call of a macro function (`CUDNN_CALL`), which is not allowed with MS compiler.
The toolchain nvcc+msvc is not correctly handled in Boost.Preprocessor module. See [this issue](https://github.com/boostorg/preprocessor/issues/15). In the meantime, the recommended workaround is to disable Variadic Macro support in Boost.
I created a [PR](https://github.com/boostorg/preprocessor/pull/18) in the Boost repo on GitHub to fix this.
10.__Provide implementation for mkstemp / Fix temporary file creation__
The code explicitely disabled the creation of temporary files because "mkstemp not available in Windows". In fact, `_mktemp` and `_unlink` are both implemented, but thay don't work as expected. I used `_tempnam` to replace `mkstemp`, and added the flag `_O_TEMPORARY` to the parameters of `_open` to automatically delete the file when it is closed. If `unlinkEarly` is not set, I added a call to `remove` in the destructor to delete the file after its closure.
I also handled the case of the default value for the `base` parameter: the path `\tmp` doesnot exist on Windows, so it is replaced by the value of the `%TMP%` environment variable in `NormalizeTempPrefix`.
