如何在代码C中为类型void ** ptr创建Fortran接口 [英] How to create Fortran interface for type void ** ptr in code C

问题描述

我是新的使用Fortran，并为ac功能如下：

I am new to use Fortran, and for a c function like below:

cudaError_t cudaMalloc  (void** devPtr, size_t size)

Allocates size bytes of linear memory on the device and returns in *devPtr a pointer to the allocated memory. The allocated memory is suitably aligned for any kind of variable. The memory is not cleared. cudaMalloc() returns cudaErrorMemoryAllocation in case of failure.

Parameters:
devPtr  - Pointer to allocated device memory
size    - Requested allocation size in bytes

Returns:
cudaSuccess, cudaErrorMemoryAllocation

我想创建一个Fortran接口来使用这个c函数，但是如何修复void ** ptr？谁能帮助我？提前感谢！

I want to create an Fortran interface to use this c function but how to fix void** ptr? Can anyone help me? Thanks in advance!

推荐答案

我不知道它是否会正常工作与设备指针（即，如果 cudaMalloc 可以从非CUDA C）调用，但一般在Fortran-C互操作性中，你表示 void * as 类型（c_ptr）从 iso_c_binding 模块。 C可互操作的过程默认通过引用传递它们的参数，所以这应该工作：

I have no idea whether it will work OK with the device pointers (i.e., if cudaMalloc is callable from non-CUDA C), but generally in Fortran-C interoperability you represent void* as type(c_ptr) from the iso_c_binding module. C interoperable procedures pass their arguments by reference by default, so this should work:

integer(c_int) function cudaMalloc(devPtr, size) bind(C,name="cudaMalloc")
  use iso_c_binding
  type(c_ptr) :: devPtr
  integer(c_size_t), value :: size
end function

指针通过引用传递，以便C侧看到一个指向指针的指针，并且可以改变它来存储

The pointer is passed by reference, so that the C side sees a pointer to pointer and can change it to store the value of the device pointer.

还有一些工作，你也可以用返回代码定义枚举。

With some more work you can also define the enumeration with the return codes.

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