diff --git a/lib/include/bofstd/bofstd.h b/lib/include/bofstd/bofstd.h
index a0cfe7e..76f9e73 100644
--- a/lib/include/bofstd/bofstd.h
+++ b/lib/include/bofstd/bofstd.h
@@ -40,12 +40,16 @@ cmake -DCMAKE_TOOLCHAIN_FILE=C:/pro/vcpkg/scripts/buildsystems/vcpkg.cmake -DBUI
 #include <Windows.h>
 typedef bool(WINAPI *BofSignalHandler)(uint32_t);
 #else
-typedef bool (*BofSignalHandler)(uint32_t);
-#endif
-using BofAssertCallback = std::function<BOFERR(const std::string &_rFile_S, uint32_t _Line_U32, const std::string &_rMasg_S)>;
 #if defined(__EMSCRIPTEN__)
+#include <emscripten/html5.h> //for emscripten_performance_now in Bof_RdTsc
 using BofEmscriptenCallback = std::function<BOFERR(void *)>;
+#else
+#include <x86intrin.h> 	//for __rdtsc in Bof_RdTsc
+#endif
+typedef bool (*BofSignalHandler)(uint32_t);
 #endif
+
+using BofAssertCallback = std::function<BOFERR(const std::string &_rFile_S, uint32_t _Line_U32, const std::string &_rMasg_S)>;
 #include <bofstd_export.h> //Autogenerated by cmake
 
 #define BOF onbings::bof
@@ -646,10 +650,16 @@ extern uint32_t GL_BofDbgPrintfStartTime_U32;
 // Intrinsyc fct
 inline BOFSTD_EXPORT uint64_t Bof_RdTsc()
 {
-  // uint32_t low, high;
-  // asm volatile ("rdtsc" : "=a" (low), "=d" (high));
-  // return (((uint64_t)high << 32) | low);
+#if defined(__EMSCRIPTEN__)
+  /*
+  uint32_t Low_U32, High_U32;
+  asm volatile ("rdtsc" : "=a" (Low_U32), "=d" (High_U32));
+  return (((uint64_t)High_U32 << 32) | Low_U32);
+  */
+  return static_cast<uint64_t>(emscripten_performance_now() * 1000000.0);  //Calls JavaScript performance.now(), returns a high precision wallclock time value in msecs.
+#else
   return __rdtsc();
+#endif
 }
 BOFSTD_EXPORT uint32_t Bof_MeasureCpuSpeedInMHz();
 
diff --git a/tests/src/ut_circularbuffer.cpp b/tests/src/ut_circularbuffer.cpp
index 40c3424..1d6d504 100644
--- a/tests/src/ut_circularbuffer.cpp
+++ b/tests/src/ut_circularbuffer.cpp
@@ -659,7 +659,7 @@ TEST(CircularBuffer_Test, Perf)
       Index_U32 = 0;
     }
   }
-  printf("%zd Push Min %zd Mean %zd Max %zd Lck %zd\n", Profiler.GetNbSample(0), Profiler.GetMin(0), Profiler.GetMean(0), Profiler.GetMax(0), Profiler.GetLockCount(0));
+  printf("%llu Push Min %llu Mean %llu Max %llu Lck %llu\n", Profiler.GetNbSample(0), Profiler.GetMin(0), Profiler.GetMean(0), Profiler.GetMax(0), Profiler.GetLockCount(0));
 
   Index_U32 = 0;
   for (i_U32 = 0; i_U32 < NB_QUEUE_OP; i_U32++)
@@ -676,7 +676,7 @@ TEST(CircularBuffer_Test, Perf)
     }
   }
   EXPECT_NE(Cb.Pop(&Item_X, 1000, nullptr, nullptr), BOF_ERR_NO_ERROR);
-  printf("%zu Pop Min %zu Mean %zu Max %zu Lck %zu\n", Profiler.GetNbSample(1), Profiler.GetMin(1), Profiler.GetMean(1), Profiler.GetMax(1), Profiler.GetLockCount(1));
+  printf("%llu Pop Min %llu Mean %llu Max %llu Lck %llu\n", Profiler.GetNbSample(1), Profiler.GetMin(1), Profiler.GetMean(1), Profiler.GetMax(1), Profiler.GetLockCount(1));
 }
 
 TEST(CircularBuffer_Test, PerfThread)
@@ -765,22 +765,22 @@ TEST(CircularBuffer_Test, PerfThread)
   for (i_U32 = 0; i_U32 < NB_QUEUE_PRODUCER_CONSUMER; i_U32++)
   {
     NbLastMax_U32 = Profiler.GetLastMax(i_U32, pLastMax_X);
-    printf("NbOp %zu NbMax %d Push[%d] Min %zu Mean %zu Max %zu Lck %zu\n", Profiler.GetNbSample(i_U32), NbLastMax_U32, i_U32, Profiler.GetMin(i_U32), Profiler.GetMean(i_U32), Profiler.GetMax(i_U32), Profiler.GetLockCount(i_U32));
+    printf("NbOp %llu NbMax %d Push[%d] Min %llu Mean %llu Max %llu Lck %llu\n", Profiler.GetNbSample(i_U32), NbLastMax_U32, i_U32, Profiler.GetMin(i_U32), Profiler.GetMean(i_U32), Profiler.GetMax(i_U32), Profiler.GetLockCount(i_U32));
     EXPECT_EQ(Profiler.GetNbSample(i_U32), NB_QUEUE_OP);
     for (j_U32 = 0; j_U32 < NbLastMax_U32; j_U32++)
     {
-      printf("  Index %zu Max %zu\n", pLastMax_X[j_U32].MaxIndex_U64, pLastMax_X[j_U32].Max);
+      printf("  Index %llu Max %llu\n", pLastMax_X[j_U32].MaxIndex_U64, pLastMax_X[j_U32].Max);
     }
   }
   printf("---POP---------------------------\n");
   for (i_U32 = NB_QUEUE_PRODUCER_CONSUMER; i_U32 < (NB_QUEUE_PRODUCER_CONSUMER + NB_QUEUE_PRODUCER_CONSUMER); i_U32++)
   {
     NbLastMax_U32 = Profiler.GetLastMax(i_U32, pLastMax_X);
-    printf("NbOp %zu NbMax %d Pop[%d] Min %zu Mean %zu Max %zu Lck %zu\n", Profiler.GetNbSample(i_U32), NbLastMax_U32, i_U32, Profiler.GetMin(i_U32), Profiler.GetMean(i_U32), Profiler.GetMax(i_U32), Profiler.GetLockCount(i_U32));
+    printf("NbOp %llu NbMax %d Pop[%d] Min %llu Mean %llu Max %llu Lck %llu\n", Profiler.GetNbSample(i_U32), NbLastMax_U32, i_U32, Profiler.GetMin(i_U32), Profiler.GetMean(i_U32), Profiler.GetMax(i_U32), Profiler.GetLockCount(i_U32));
     EXPECT_EQ(Profiler.GetNbSample(i_U32), NB_QUEUE_OP);
     for (j_U32 = 0; j_U32 < NbLastMax_U32; j_U32++)
     {
-      printf("  Index %zu Max %zu\n", pLastMax_X[j_U32].MaxIndex_U64, pLastMax_X[j_U32].Max);
+      printf("  Index %llu Max %llu\n", pLastMax_X[j_U32].MaxIndex_U64, pLastMax_X[j_U32].Max);
     }
   }
 }
\ No newline at end of file
diff --git a/vcpkg.json b/vcpkg.json
index 5b72a89..800aed1 100644
--- a/vcpkg.json
+++ b/vcpkg.json
@@ -1,6 +1,6 @@
 {
   "name": "bofstd",
-  "version": "5.6.0.3",
+  "version": "5.6.0.4",
   "description": "The onbings general purpose C++ Multiplatform library",
   "dependencies": [
     {