diff --git a/DataFormats/simulation/include/SimulationDataFormat/ConstMCTruthContainer.h b/DataFormats/simulation/include/SimulationDataFormat/ConstMCTruthContainer.h
index 2213ad1bb8d9d..91099201a016f 100644
--- a/DataFormats/simulation/include/SimulationDataFormat/ConstMCTruthContainer.h
+++ b/DataFormats/simulation/include/SimulationDataFormat/ConstMCTruthContainer.h
@@ -131,15 +131,16 @@ class ConstMCTruthContainerView
  public:
   ConstMCTruthContainerView(gsl::span<const char> const bufferview) : mStorage(bufferview){};
   ConstMCTruthContainerView(ConstMCTruthContainer<TruthElement> const& cont) : mStorage(gsl::span<const char>(cont)){};
+  // be explicit that we want nullptr / 0 for an uninitialized container (needs (void)0 to avoid false codechecker warning)
 #ifdef MS_GSL_V3
-  // be explicit that we want nullptr / 0 for an uninitialized container
   ConstMCTruthContainerView() : mStorage{nullptr, static_cast<gsl::span<const char>::size_type>(0)}
   {
+    (void)0;
   }
 #else
-  // be explicit that we want nullptr / 0 for an uninitialized container
   ConstMCTruthContainerView() : mStorage{nullptr, static_cast<gsl::span<const char>::index_type>(0)}
   {
+    (void)0;
   }
 #endif
   ConstMCTruthContainerView(const ConstMCTruthContainerView&) = default;
diff --git a/GPU/GPUTracking/Benchmark/standalone.cxx b/GPU/GPUTracking/Benchmark/standalone.cxx
index fdec0be289b3e..3e1dc69bb91ed 100644
--- a/GPU/GPUTracking/Benchmark/standalone.cxx
+++ b/GPU/GPUTracking/Benchmark/standalone.cxx
@@ -35,11 +35,11 @@
 #ifndef _WIN32
 #include <unistd.h>
 #include <sched.h>
-#include <signal.h>
+#include <csignal>
 #include <sys/types.h>
 #include <sys/wait.h>
 #include <sys/select.h>
-#include <fenv.h>
+#include <cfenv>
 #include <clocale>
 #include <sys/stat.h>
 #endif
diff --git a/GPU/GPUTracking/display/GPUDisplayBackendGlut.cxx b/GPU/GPUTracking/display/GPUDisplayBackendGlut.cxx
index 0698c15fc0253..758ad5907b2b6 100644
--- a/GPU/GPUTracking/display/GPUDisplayBackendGlut.cxx
+++ b/GPU/GPUTracking/display/GPUDisplayBackendGlut.cxx
@@ -26,13 +26,13 @@
 using namespace GPUCA_NAMESPACE::gpu;
 static GPUDisplayBackendGlut* me = nullptr;
 
-void GPUDisplayBackendGlut::displayFunc(void)
+void GPUDisplayBackendGlut::displayFunc()
 {
   me->DrawGLScene();
   glutSwapBuffers();
 }
 
-void GPUDisplayBackendGlut::glutLoopFunc(void)
+void GPUDisplayBackendGlut::glutLoopFunc()
 {
   me->HandleSendKey();
   displayFunc();
diff --git a/GPU/GPUTracking/display/GPUDisplayBackendGlut.h b/GPU/GPUTracking/display/GPUDisplayBackendGlut.h
index 77426ebcac656..fbf0a25fe6d93 100644
--- a/GPU/GPUTracking/display/GPUDisplayBackendGlut.h
+++ b/GPU/GPUTracking/display/GPUDisplayBackendGlut.h
@@ -35,8 +35,8 @@ class GPUDisplayBackendGlut : public GPUDisplayBackend
  private:
   int OpenGLMain() override;
 
-  static void displayFunc(void);
-  static void glutLoopFunc(void);
+  static void displayFunc();
+  static void glutLoopFunc();
   static void keyboardUpFunc(unsigned char key, int x, int y);
   static void keyboardDownFunc(unsigned char key, int x, int y);
   static void specialUpFunc(int key, int x, int y);
diff --git a/GPU/GPUTracking/qa/genEvents.cxx b/GPU/GPUTracking/qa/genEvents.cxx
index 4c99df72b8b46..01511867af1ad 100644
--- a/GPU/GPUTracking/qa/genEvents.cxx
+++ b/GPU/GPUTracking/qa/genEvents.cxx
@@ -13,7 +13,7 @@
 
 #include <iostream>
 #include <fstream>
-#include <string.h>
+#include <cstring>
 #include <sys/stat.h>
 
 #include "Rtypes.h"
diff --git a/GPU/GPUTracking/qa/genEvents.h b/GPU/GPUTracking/qa/genEvents.h
index fe3c6f4e10cb6..42f064481bd94 100644
--- a/GPU/GPUTracking/qa/genEvents.h
+++ b/GPU/GPUTracking/qa/genEvents.h
@@ -54,7 +54,7 @@ class genEvents
   int RecalculateSlice(GPUTPCGMPhysicalTrackModel& t, int& iSlice);
   double GetGaus(double sigma);
 
-  TH1F* mClusterError[3][2] = {{0, 0}, {0, 0}, {0, 0}};
+  TH1F* mClusterError[3][2] = {{nullptr, nullptr}, {nullptr, nullptr}, {nullptr, nullptr}};
 
   struct GenCluster {
     int sector;