/*
 * Copyright (C) 2011 Florian Rathgeber, florian.rathgeber@gmail.com
 *
 * This code is licensed under the MIT License.  See the FindCUDA.cmake script
 * for the text of the license.
 *
 * Based on code by Christopher Bruns published on Stack Overflow (CC-BY):
 * http://stackoverflow.com/questions/2285185
 */

#include <stdio.h>
#include <cuda_runtime.h>

int main() {
  int deviceCount, device, major = 9999, minor = 9999;
  int gpuDeviceCount = 0;
  struct cudaDeviceProp properties;

  if (cudaGetDeviceCount(&deviceCount) != cudaSuccess)
    {
      printf("Couldn't get device count: %s\n", cudaGetErrorString(cudaGetLastError()));
      return 1;
    }
  /* machines with no GPUs can still report one emulation device */
  for (device = 0; device < deviceCount; ++device) {
    cudaGetDeviceProperties(&properties, device);
    if (properties.major != 9999) {/* 9999 means emulation only */
      ++gpuDeviceCount;
      /*  get minimum compute capability of all devices */
      if (major > properties.major) {
        major = properties.major;
        minor = properties.minor;
      } else if (minor > properties.minor) {
        minor = properties.minor;
      }
    }
  }

  /* don't just return the number of gpus, because other runtime cuda
     errors can also yield non-zero return values */
  if (gpuDeviceCount > 0) {
    if (major == 2 && minor == 1)
      {
        // There is no --arch compute_21 flag for nvcc, so force minor to 0
        minor = 0;
      }
    /* this output will be parsed by FindCUDA.cmake */
    printf("%d%d", major, minor);
    return 0; /* success */
  }
  return 1; /* failure */
}