GPU: Better workaround for clang problem with static constexpr members of references

GPU/Common/GPUCommonTypeTraits.h

@@ -22,7 +22,7 @@
 #include <type_traits>
 #endif
 #else
-// We just reimplement some type traits in std for the GPU
+// We just reimplement some type traits in std for the GPU // TODO: Check if meanwhile we can get rid of GPUCommonTypeTraits and GPUCommonArray, and just use the std headers.
 namespace std
 {
 template <bool B, class T, class F>
@@ -35,6 +35,7 @@ struct conditional<false, T, F> {
 };
 template <bool B, class T, class F>
 using contitional_t = typename conditional<B, T, F>::type;
+
 template <class T, class U>
 struct is_same {
   static constexpr bool value = false;
@@ -45,13 +46,15 @@ struct is_same<T, T> {
 };
 template <class T, class U>
 static constexpr bool is_same_v = is_same<T, U>::value;
+
 template <bool B, class T = void>
 struct enable_if {
 };
 template <class T>
 struct enable_if<true, T> {
   typedef T type;
 };
+
 template <class T>
 struct remove_cv {
   typedef T type;
@@ -68,6 +71,9 @@ template <class T>
 struct remove_cv<const volatile T> {
   typedef T type;
 };
+template <class T>
+using remove_cv_t = typename remove_cv<T>::type;
+
 template <class T>
 struct remove_const {
   typedef T type;
@@ -76,6 +82,9 @@ template <class T>
 struct remove_const<const T> {
   typedef T type;
 };
+template <class T>
+using remove_const_t = typename remove_const<T>::type;
+
 template <class T>
 struct remove_volatile {
   typedef T type;
@@ -84,6 +93,9 @@ template <class T>
 struct remove_volatile<volatile T> {
   typedef T type;
 };
+template <class T>
+using remove_volatile_t = typename remove_volatile<T>::type;
+
 template <class T>
 struct is_pointer_t {
   static constexpr bool value = false;
@@ -95,6 +107,36 @@ struct is_pointer_t<T*> {
 template <class T>
 struct is_pointer : is_pointer_t<typename std::remove_cv<T>::type> {
 };
+
+template <class T>
+struct remove_reference {
+  typedef T type;
+};
+template <class T>
+struct remove_reference<T&> {
+  typedef T type;
+};
+template <class T>
+struct remove_reference<T&&> {
+  typedef T type;
+};
+template <class T>
+using remove_reference_t = typename remove_reference<T>::type;
+
+template <class T>
+struct is_member_pointer_helper {
+  static constexpr bool value = false;
+};
+template <class T, class U>
+struct is_member_pointer_helper<T U::*> {
+  static constexpr bool value = true;
+};
+template <class T>
+struct is_member_pointer : is_member_pointer_helper<typename std::remove_cv<T>::type> {
+};
+template <class T>
+static constexpr bool is_member_pointer_v = is_member_pointer<T>::value;
+
 } // namespace std
 #endif
 

GPU/GPUTracking/Base/cuda/CMakeLists.txt

@@ -68,7 +68,7 @@ set(GPU_RTC_BIN ${CMAKE_CURRENT_BINARY_DIR}/GPUReconstructionCUDArtc)
 add_custom_command(
     OUTPUT ${GPU_RTC_BIN}.src
     COMMAND cp ${GPUDIR}/Base/cuda/GPUReconstructionCUDAIncludesSystem.h ${GPU_RTC_BIN}.src
-    COMMAND ${CMAKE_CXX_COMPILER} ${GPU_RTC_DEFINES} ${GPU_RTC_INCLUDES} -std=c++${CMAKE_CUDA_STANDARD} -D__CUDA_ARCH__=${RTC_CUDA_ARCH} -D__CUDACC__ -x c++ -nostdinc -E -P ${GPU_RTC_SRC} >> ${GPU_RTC_BIN}.src
+    COMMAND ${CMAKE_CUDA_COMPILER} ${GPU_RTC_DEFINES} ${GPU_RTC_INCLUDES} -std=c++${CMAKE_CUDA_STANDARD} -D__CUDA_ARCH__=${RTC_CUDA_ARCH} -D__CUDACC__ -x c++ -E -Xcompiler "-nostdinc -P" ${GPU_RTC_SRC} >> ${GPU_RTC_BIN}.src
     MAIN_DEPENDENCY ${GPU_RTC_SRC}
     IMPLICIT_DEPENDS CXX ${GPU_RTC_SRC}
     COMMAND_EXPAND_LISTS

GPU/GPUTracking/Base/cuda/GPUReconstructionCUDAGenRTC.cxx

@@ -38,11 +38,7 @@ int32_t GPUReconstructionCUDA::genRTC(std::string& filename, uint32_t& nCompile)
 {
   std::string rtcparam = std::string("#define GPUCA_RTC_CODE\n") +
                          std::string(GetProcessingSettings().rtc.optSpecialCode ? "#define GPUCA_RTC_SPECIAL_CODE(...) __VA_ARGS__\n" : "#define GPUCA_RTC_SPECIAL_CODE(...)\n") +
-#ifndef GPUCA_HIP_WORKAROUND_CONSTEXPR // TODO: Fixme, once we have C++ P2280R4 in Clang
                          std::string(GetProcessingSettings().rtc.optConstexpr ? "#define GPUCA_RTC_CONSTEXPR constexpr\n" : "#define GPUCA_RTC_CONSTEXPR\n") +
-#else
-                         std::string("#define GPUCA_RTC_CONSTEXPR\n") +
-#endif
                          GPUParamRTC::generateRTCCode(param(), GetProcessingSettings().rtc.optConstexpr);
   if (filename == "") {
     filename = "/tmp/o2cagpu_rtc_";

GPU/GPUTracking/Base/cuda/GPUReconstructionCUDAInternals.h

@@ -79,7 +79,7 @@ class GPUDebugTiming
   bool mDo;
 };
 
-static_assert(std::is_convertible<cudaEvent_t, void*>::value, "CUDA event type incompatible to deviceEvent");
+static_assert(std::is_convertible_v<cudaEvent_t, void*>, "CUDA event type incompatible to deviceEvent");
 
 } // namespace o2::gpu
 

GPU/GPUTracking/Base/hip/CMakeLists.txt

@@ -115,7 +115,7 @@ set(GPU_RTC_BIN ${CMAKE_CURRENT_BINARY_DIR}/GPUReconstructionHIPrtc)
 add_custom_command(
     OUTPUT ${GPU_RTC_BIN}.src
     COMMAND cp ${GPUDIR}/Base/hip/GPUReconstructionHIPIncludesSystem.h ${GPU_RTC_BIN}.src
-    COMMAND ${CMAKE_CXX_COMPILER} ${GPU_RTC_DEFINES} ${GPU_RTC_INCLUDES} -std=c++${CMAKE_HIP_STANDARD} -D__HIPCC__ -D__HIP_DEVICE_COMPILE__ -x c++ -nostdinc -E -P ${GPU_RTC_SRC} >> ${GPU_RTC_BIN}.src
+    COMMAND ${CMAKE_HIP_COMPILER} ${GPU_RTC_DEFINES} ${GPU_RTC_INCLUDES} -std=c++${CMAKE_HIP_STANDARD} -D__HIPCC__ -D__HIP_DEVICE_COMPILE__ -x c++ -nostdinc -E -P ${GPU_RTC_SRC} >> ${GPU_RTC_BIN}.src
     MAIN_DEPENDENCY ${GPU_RTC_SRC}
     IMPLICIT_DEPENDS CXX ${GPU_RTC_SRC}
     DEPENDS ${MODULE}_HIPIFIED
@@ -270,8 +270,3 @@ add_dependencies(GPUTrackingHIPExternalProvider O2::GPUTracking) # must not depe
 if(NOT DEFINED GPUCA_HIP_HIPIFY_FROM_CUDA OR "${GPUCA_HIP_HIPIFY_FROM_CUDA}")
   add_dependencies(GPUTrackingHIPExternalProvider ${MODULE}_HIPIFIED)
 endif()
-
-set_source_files_properties("${GPUCA_HIP_SOURCE_DIR}/GPUReconstructionHIPGenRTC.cxx"
-TARGET_DIRECTORY O2::GPUTrackingHIP
-PROPERTIES
-COMPILE_DEFINITIONS "GPUCA_HIP_WORKAROUND_CONSTEXPR")

GPU/GPUTracking/Base/opencl/GPUReconstructionOCL.cxx

@@ -18,7 +18,7 @@
 
 #include <map>
 
-static_assert(std::is_convertible<cl_event, void*>::value, "OpenCL event type incompatible to deviceEvent");
+static_assert(std::is_convertible_v<cl_event, void*>, "OpenCL event type incompatible to deviceEvent");
 
 #define GPUErrorReturn(...) \
   {                         \

GPU/GPUTracking/Definitions/GPUGetConstexpr.h

@@ -0,0 +1,67 @@
+// Copyright 2019-2020 CERN and copyright holders of ALICE O2.
+// See https://alice-o2.web.cern.ch/copyright for details of the copyright holders.
+// All rights not expressly granted are reserved.
+//
+// This software is distributed under the terms of the GNU General Public
+// License v3 (GPL Version 3), copied verbatim in the file "COPYING".
+//
+// In applying this license CERN does not waive the privileges and immunities
+// granted to it by virtue of its status as an Intergovernmental Organization
+// or submit itself to any jurisdiction.
+
+/// \file GPUGetConstexpr.h
+/// \author David Rohr
+
+#ifndef GPUGETCONSTEXPR_H
+#define GPUGETCONSTEXPR_H
+
+#include "GPUCommonDef.h"
+#include "GPUCommonTypeTraits.h"
+
+// This is a temporary workaround required for clang (with c++20), until we can go to C++23 with P2280R4, which allows getting constexpr static values from references
+
+#if defined(__clang__) && __cplusplus >= 202002L && __cplusplus < 202302L
+
+namespace o2::gpu::internal
+{
+
+#define GPUCA_GET_CONSTEXPR(obj, val) ( \
+  std::is_member_pointer_v<decltype(&std::remove_reference_t<decltype(obj)>::val)> ? o2::gpu::internal::getConstexpr(&std::remove_reference_t<decltype(obj)>::val, o2::gpu::internal::getConstexprHelper<decltype(&std::remove_reference_t<decltype(obj)>::val), decltype(&obj)>(&obj).value) : o2::gpu::internal::getConstexpr(&std::remove_reference_t<decltype(obj)>::val, o2::gpu::internal::getConstexprHelper<decltype(&std::remove_reference_t<decltype(obj)>::val), decltype(&obj)>().value))
+
+template <class T, class S>
+struct getConstexprHelper;
+
+template <class T, class S>
+  requires(!std::is_member_pointer_v<T>)
+struct getConstexprHelper<T, S> {
+  GPUdi() constexpr getConstexprHelper(const void* = nullptr) {}
+  static constexpr const void* value = nullptr;
+};
+
+template <class T, class S>
+  requires(std::is_member_pointer_v<T>)
+struct getConstexprHelper<T, S> {
+  GPUdi() constexpr getConstexprHelper(const S& v) : value(v) {}
+  GPUdDefault() constexpr getConstexprHelper() = default;
+  const S value = nullptr;
+};
+
+GPUdi() constexpr auto getConstexpr(const auto* v, const void* = nullptr)
+{
+  return *v;
+}
+
+GPUdi() constexpr auto getConstexpr(const auto v, const auto w)
+{
+  return w->*v;
+}
+
+} // namespace o2::gpu::internal
+
+#else // __clang__
+
+#define GPUCA_GET_CONSTEXPR(obj, val) (obj).val
+
+#endif
+
+#endif // GPUGETCONSTEXPR_H

GPU/GPUTracking/Merger/GPUTPCGMMerger.cxx

@@ -235,7 +235,7 @@ int64_t GPUTPCGMMerger::GetTrackLabelA(const S& trk) const
 {
   GPUTPCGMSectorTrack* sectorTrack = nullptr;
   int32_t nClusters = 0;
-  if constexpr (std::is_same<S, GPUTPCGMBorderTrack&>::value) {
+  if constexpr (std::is_same_v<S, GPUTPCGMBorderTrack&>) {
     sectorTrack = &mSectorTrackInfos[trk.TrackID()];
     nClusters = sectorTrack->OrigTrack()->NHits();
   } else {
@@ -244,7 +244,7 @@ int64_t GPUTPCGMMerger::GetTrackLabelA(const S& trk) const
   auto acc = GPUTPCTrkLbl<false, GPUTPCTrkLbl_ret>(resolveMCLabels<T>(GetConstantMem()->ioPtrs.clustersNative ? GetConstantMem()->ioPtrs.clustersNative->clustersMCTruth : nullptr, GetConstantMem()->ioPtrs.mcLabelsTPC), 0.5f);
   for (int32_t i = 0; i < nClusters; i++) {
     int32_t id;
-    if constexpr (std::is_same<S, GPUTPCGMBorderTrack&>::value) {
+    if constexpr (std::is_same_v<S, GPUTPCGMBorderTrack&>) {
       const GPUTPCTracker& tracker = GetConstantMem()->tpcTrackers[sectorTrack->Sector()];
       const GPUTPCHitId& ic = tracker.TrackHits()[sectorTrack->OrigTrack()->FirstHitID() + i];
       id = tracker.Data().ClusterDataIndex(tracker.Data().Row(ic.RowIndex()), ic.HitIndex()) + GetConstantMem()->ioPtrs.clustersNative->clusterOffset[sectorTrack->Sector()][0];

GPU/GPUTracking/Merger/GPUTPCGMO2Output.cxx

@@ -20,6 +20,7 @@
 #include "DataFormatsTPC/PIDResponse.h"
 #include "TPCFastTransform.h"
 #include "CorrectionMapsHelper.h"
+#include "GPUGetConstexpr.h"
 
 #ifndef GPUCA_GPUCODE
 #include "SimulationDataFormat/ConstMCTruthContainer.h"
@@ -141,10 +142,10 @@ GPUdii() void GPUTPCGMO2Output::Thread<GPUTPCGMO2Output::output>(int32_t nBlocks
 
     oTrack.setChi2(tracks[i].GetParam().GetChi2());
     auto& outerPar = tracks[i].OuterParam();
-    if GPUCA_RTC_CONSTEXPR (param.par.dodEdx) {
+    if GPUCA_RTC_CONSTEXPR (GPUCA_GET_CONSTEXPR(param.par, dodEdx)) {
       if (param.dodEdxEnabled) {
         oTrack.setdEdx(tracksdEdx[i]);
-        if GPUCA_RTC_CONSTEXPR (param.rec.tpc.dEdxClusterRejectionFlagMask != param.rec.tpc.dEdxClusterRejectionFlagMaskAlt) {
+        if GPUCA_RTC_CONSTEXPR (GPUCA_GET_CONSTEXPR(param.rec.tpc, dEdxClusterRejectionFlagMask) != GPUCA_GET_CONSTEXPR(param.rec.tpc, dEdxClusterRejectionFlagMaskAlt)) {
           oTrack.setdEdxAlt(tracksdEdxAlt[i]);
         } else {
           oTrack.setdEdxAlt(tracksdEdx[i]);

GPU/GPUTracking/Merger/GPUTPCGMTrackParam.cxx

@@ -39,6 +39,7 @@
 #include "GPUTPCConvertImpl.h"
 #include "GPUTPCGMMergerTypes.h"
 #include "GPUParam.inc"
+#include "GPUGetConstexpr.h"
 
 #ifdef GPUCA_CADEBUG_ENABLED
 #include "../utils/qconfig.h"
@@ -216,12 +217,12 @@ GPUd() bool GPUTPCGMTrackParam::Fit(GPUTPCGMMerger* GPUrestrict() merger, int32_
           continue;
         }
       } else if (allowModification && lastRow != 255 && CAMath::Abs(cluster.row - lastRow) > 1) {
-        if GPUCA_RTC_CONSTEXPR (param.par.dodEdx) {
+        if GPUCA_RTC_CONSTEXPR (GPUCA_GET_CONSTEXPR(param.par, dodEdx)) {
           bool dodEdx = param.dodEdxEnabled && param.rec.tpc.adddEdxSubThresholdClusters && iWay == nWays - 1 && CAMath::Abs(cluster.row - lastRow) == 2 && cluster.leg == clusters[maxN - 1].leg;
           dodEdx = AttachClustersPropagate(merger, cluster.sector, lastRow, cluster.row, iTrk, cluster.leg == clusters[maxN - 1].leg, prop, inFlyDirection, GPUCA_MAX_SIN_PHI, dodEdx);
           if (dodEdx) {
             dEdx.fillSubThreshold(lastRow - wayDirection);
-            if GPUCA_RTC_CONSTEXPR (param.rec.tpc.dEdxClusterRejectionFlagMask != param.rec.tpc.dEdxClusterRejectionFlagMaskAlt) {
+            if GPUCA_RTC_CONSTEXPR (GPUCA_GET_CONSTEXPR(param.rec.tpc, dEdxClusterRejectionFlagMask) != GPUCA_GET_CONSTEXPR(param.rec.tpc, dEdxClusterRejectionFlagMaskAlt)) {
               dEdxAlt.fillSubThreshold(lastRow - wayDirection);
             }
           }
@@ -371,7 +372,7 @@ GPUd() bool GPUTPCGMTrackParam::Fit(GPUTPCGMMerger* GPUrestrict() merger, int32_
           CADEBUG(printf("Reinit linearization\n"));
           prop.SetTrack(this, prop.GetAlpha());
         }
-        if GPUCA_RTC_CONSTEXPR (param.par.dodEdx) {
+        if GPUCA_RTC_CONSTEXPR (GPUCA_GET_CONSTEXPR(param.par, dodEdx)) {
           if (param.dodEdxEnabled && iWay == nWays - 1 && cluster.leg == clusters[maxN - 1].leg) { // TODO: Costimize flag to remove, and option to remove double-clusters
             bool acc = (clusterState & param.rec.tpc.dEdxClusterRejectionFlagMask) == 0, accAlt = (clusterState & param.rec.tpc.dEdxClusterRejectionFlagMaskAlt) == 0;
             if (acc || accAlt) {
@@ -395,7 +396,7 @@ GPUd() bool GPUTPCGMTrackParam::Fit(GPUTPCGMMerger* GPUrestrict() merger, int32_
               if (acc) {
                 dEdx.fillCluster(qtot, qmax, cluster.row, cluster.sector, mP[2], mP[3], merger->GetConstantMem()->calibObjects, zz, pad, relTime);
               }
-              if GPUCA_RTC_CONSTEXPR (param.rec.tpc.dEdxClusterRejectionFlagMask != param.rec.tpc.dEdxClusterRejectionFlagMaskAlt) {
+              if GPUCA_RTC_CONSTEXPR (GPUCA_GET_CONSTEXPR(param.rec.tpc, dEdxClusterRejectionFlagMask) != GPUCA_GET_CONSTEXPR(param.rec.tpc, dEdxClusterRejectionFlagMaskAlt)) {
                 if (accAlt) {
                   dEdxAlt.fillCluster(qtot, qmax, cluster.row, cluster.sector, mP[2], mP[3], merger->GetConstantMem()->calibObjects, zz, pad, relTime);
                 }
@@ -436,7 +437,7 @@ GPUd() bool GPUTPCGMTrackParam::Fit(GPUTPCGMMerger* GPUrestrict() merger, int32_
 
   if (param.par.dodEdx && param.dodEdxEnabled) {
     dEdx.computedEdx(merger->MergedTracksdEdx()[iTrk], param);
-    if GPUCA_RTC_CONSTEXPR (param.rec.tpc.dEdxClusterRejectionFlagMask != param.rec.tpc.dEdxClusterRejectionFlagMaskAlt) {
+    if GPUCA_RTC_CONSTEXPR (GPUCA_GET_CONSTEXPR(param.rec.tpc, dEdxClusterRejectionFlagMask) != GPUCA_GET_CONSTEXPR(param.rec.tpc, dEdxClusterRejectionFlagMaskAlt)) {
       dEdxAlt.computedEdx(merger->MergedTracksdEdxAlt()[iTrk], param);
     }
   }

GPU/GPUTracking/qa/GPUQAHelper.h

@@ -48,7 +48,7 @@ class GPUTPCTrkLbl
   }
   inline void addLabel(uint32_t elementId)
   {
-    if constexpr (std::is_same<T, AliHLTTPCClusterMCWeight>::value) {
+    if constexpr (std::is_same_v<T, AliHLTTPCClusterMCWeight>) {
       for (uint32_t i = 0; i < sizeof(mClusterLabels[elementId]) / sizeof(mClusterLabels[elementId].fClusterID[0]); i++) {
         const auto& element = mClusterLabels[elementId].fClusterID[i];
         if (element.fMCID >= 0) {
@@ -101,7 +101,7 @@ class GPUTPCTrkLbl
         }
       }
       auto& bestLabel = mLabels[bestLabelNum].first;
-      if constexpr (std::is_same<T, AliHLTTPCClusterMCWeight>::value && WEIGHT) {
+      if constexpr (std::is_same_v<T, AliHLTTPCClusterMCWeight> && WEIGHT) {
         *labelWeight = bestLabel.fWeight;
         *totalWeight = mTotalWeight;
         *maxCount = bestLabelCount;
@@ -147,7 +147,7 @@ struct GPUTPCTrkLbl_ret {
 template <bool WEIGHT = false, class U = void, class T, template <class> class S, typename... Args>
 static inline auto GPUTPCTrkLbl(const S<T>* x, Args... args)
 {
-  if constexpr (std::is_same<U, void>::value) {
+  if constexpr (std::is_same_v<U, void>) {
     return internal::GPUTPCTrkLbl<WEIGHT, T, S<T>>(x, args...);
   } else {
     return internal::GPUTPCTrkLbl<WEIGHT, T, S<T>, U>(x, args...);
@@ -159,7 +159,7 @@ static inline auto GPUTPCTrkLbl(const AliHLTTPCClusterMCLabel* x, Args... args)
 {
   using S = AliHLTTPCClusterMCLabel;
   using T = AliHLTTPCClusterMCWeight;
-  if constexpr (std::is_same<U, void>::value) {
+  if constexpr (std::is_same_v<U, void>) {
     return internal::GPUTPCTrkLbl<WEIGHT, T, S>(x, args...);
   } else {
     return internal::GPUTPCTrkLbl<WEIGHT, T, S, U>(x, args...);

GPU/GPUTracking/utils/bitfield.h

@@ -93,7 +93,7 @@ class bitfield
   }
 
 #if !defined(GPUCA_GPUCODE_DEVICE)
-  static_assert(std::is_integral<S>::value, "Storage type non integral");
+  static_assert(std::is_integral_v<S>, "Storage type non integral");
   static_assert(sizeof(S) >= sizeof(T), "Storage type has insufficient capacity");
 #endif
 

GPU/GPUTracking/utils/qconfig.cxx

@@ -126,7 +126,7 @@ static inline int32_t qAddOptionMainTupleElem(qConfigSettings<typename qSettings
   qConfigSettings<T> settings = settingsTup;
   return (qAddOptionType<T>(settings, ref, i, argv, argc, def));
 }
-template <typename T, int32_t index = 0, int32_t left = std::tuple_size<T>::value>
+template <typename T, int32_t index = 0, int32_t left = std::tuple_size_v<T>>
 struct qAddOptionMainTupleStruct {
   static inline int32_t qAddOptionMainTuple(qConfigSettings<typename qSettingsType<T>::settingsType> settings, T& tup, int32_t& i, const char** argv, const int argc)
   {
@@ -157,13 +157,13 @@ struct qConfigType {
   // Recursive handling of additional settings
   static inline void qProcessSetting(qConfigSettings<T>& settings, qmin_t<T> minval)
   {
-    static_assert(!std::is_same<T, bool>::value, "min option not supported for boolean settings");
+    static_assert(!std::is_same_v<T, bool>, "min option not supported for boolean settings");
     settings.checkMin = true;
     settings.min = minval.v;
   }
   static inline void qProcessSetting(qConfigSettings<T>& settings, qmax_t<T> maxval)
   {
-    static_assert(!std::is_same<T, bool>::value, "max option not supported for boolean settings");
+    static_assert(!std::is_same_v<T, bool>, "max option not supported for boolean settings");
     settings.checkMax = true;
     settings.max = maxval.v;
   }
@@ -244,7 +244,7 @@ struct qConfigType {
   static inline void qConfigHelpOption(const char* name, const char* type, const char* def, const char* optname, char optnameshort, const char* preopt, char preoptshort, int32_t optionType, const char* help, Args&&... args)
   {
     auto settings = qConfigGetSettings(args...);
-    const bool boolType = optionType != 1 && std::is_same<T, bool>::value;
+    const bool boolType = optionType != 1 && std::is_same_v<T, bool>;
     const char* arguments = settings.doSet ? " (" : (settings.doDefault || optionType == 1 || boolType) ? " [arg] (" : optionType == 2 ? " [...] (" : " arg (";
     char argBuffer[4] = {0};
     uint32_t argBufferPos = 0;