Use different exit codes for different conditions

HeterogeneousCore/CUDAUtilities/bin/cudaIsEnabled.cpp

@@ -4,23 +4,28 @@
 // CUDA headers
 #include <cuda_runtime.h>
 
+// CMSSW headers
+#include "HeterogeneousCore/Common/interface/PlatformStatus.h"
+
 // local headers
 #include "isCudaDeviceSupported.h"
 
-// returns EXIT_SUCCESS if at least one visible CUDA device can be used, or EXIT_FAILURE otherwise
+// returns PlatformStatus::Success if at least one visible CUDA device can be used,
+// or different failure codes depending on the problem.
 int main() {
   int devices = 0;
   auto status = cudaGetDeviceCount(&devices);
   if (status != cudaSuccess) {
-    return EXIT_FAILURE;
+    // could not initialise the CUDA runtime
+    return PlatformStatus::RuntimeNotAvailable;
   }
 
   // check that at least one visible CUDA device can be used
   for (int i = 0; i < devices; ++i) {
     if (isCudaDeviceSupported(i))
-      return EXIT_SUCCESS;
+      return PlatformStatus::Success;
   }
 
-  // no visible usable devices
-  return EXIT_FAILURE;
+  // could not find any usable CUDA devices
+  return PlatformStatus::DevicesNotAvailable;
 }

HeterogeneousCore/CUDAUtilities/bin/cudaIsEnabled_fallback.cpp

@@ -1,5 +1,10 @@
 // C/C++ headers
 #include <cstdlib>
 
-// always returns EXIT_FAILURE
-int main() { return EXIT_FAILURE; }
+// CMSSW headers
+#include "HeterogeneousCore/Common/interface/PlatformStatus.h"
+
+int main() {
+  // CUDA is not available on this architecture, OS and compiler combination
+  return PlatformStatus::PlatformNotAvailable;
+}

HeterogeneousCore/Common/interface/PlatformStatus.h

@@ -0,0 +1,13 @@
+#ifndef HeterogeneousCore_Common_interface_PlatformStatus_h
+#define HeterogeneousCore_Common_interface_PlatformStatus_h
+
+// Please note: these values must be kept in sync with HeterogeneousCore/Common/python/PlatformStatus.py
+
+enum PlatformStatus : int {
+  Success = 0,
+  PlatformNotAvailable = 1,  // the platform is not available for this architecture, OS or compiler
+  RuntimeNotAvailable = 2,   // the runtime could not be initialised
+  DevicesNotAvailable = 3,   // there are no visible, usable devices
+};
+
+#endif  // HeterogeneousCore_Common_interface_PlatformStatus_h

HeterogeneousCore/Common/python/PlatformStatus.py

@@ -0,0 +1,9 @@
+import enum
+
+# Please note: these values must be kept in sync with HeterogeneousCore/Common/interface/PlatformStatus.h
+
+class PlatformStatus(enum.IntEnum):
+    Success = 0 
+    PlatformNotAvailable = 1    # the platform is not available for this architecture, OS or compiler
+    RuntimeNotAvailable = 2     # the runtime could not be initialised
+    DevicesNotAvailable = 3     # there are no visible, usable devices

HeterogeneousCore/ROCmUtilities/bin/rocmIsEnabled.cpp

@@ -4,23 +4,28 @@
 // ROCm headers
 #include <hip/hip_runtime.h>
 
+// CMSSW headers
+#include "HeterogeneousCore/Common/interface/PlatformStatus.h"
+
 // local headers
 #include "isRocmDeviceSupported.h"
 
-// returns EXIT_SUCCESS if at least one visible ROCm device can be used, or EXIT_FAILURE otherwise
+// returns PlatformStatus::Success if at least one visible ROCm device can be used,
+// or different failure codes depending on the problem.
 int main() {
   int devices = 0;
   auto status = hipGetDeviceCount(&devices);
   if (status != hipSuccess) {
-    return EXIT_FAILURE;
+    // could not initialise the ROCm runtime
+    return PlatformStatus::RuntimeNotAvailable;
   }
 
   // check that at least one visible ROCm device can be used
   for (int i = 0; i < devices; ++i) {
     if (isRocmDeviceSupported(i))
-      return EXIT_SUCCESS;
+      return PlatformStatus::Success;
   }
 
-  // no visible usable devices
-  return EXIT_FAILURE;
+  // no usable ROCm devices were found
+  return PlatformStatus::DevicesNotAvailable;
 }

HeterogeneousCore/ROCmUtilities/bin/rocmIsEnabled_fallback.cpp

@@ -1,5 +1,10 @@
 // C/C++ headers
 #include <cstdlib>
 
-// always returns EXIT_FAILURE
-int main() { return EXIT_FAILURE; }
+// CMSSW headers
+#include "HeterogeneousCore/Common/interface/PlatformStatus.h"
+
+int main() {
+  // ROCm is not available on this architecture, OS and compiler combination
+  return PlatformStatus::PlatformNotAvailable;
+}