diff --git a/ref_app/ref_app.vcxproj b/ref_app/ref_app.vcxproj
index acf78b8c9..4e6589d0c 100644
--- a/ref_app/ref_app.vcxproj
+++ b/ref_app/ref_app.vcxproj
@@ -3233,6 +3233,7 @@
     </ClInclude>
     <ClInclude Include="src\util\STL_C++XX_stdfloat\stdfloat.h" />
     <ClInclude Include="src\util\utility\util_alignas.h" />
+    <ClInclude Include="src\util\utility\util_attribute.h" />
     <ClInclude Include="src\util\utility\util_baselexical_cast.h" />
     <ClInclude Include="src\util\utility\util_bit_mask.h" />
     <ClInclude Include="src\util\utility\util_communication.h" />
diff --git a/ref_app/ref_app.vcxproj.filters b/ref_app/ref_app.vcxproj.filters
index 3deb12c95..2e21722da 100644
--- a/ref_app/ref_app.vcxproj.filters
+++ b/ref_app/ref_app.vcxproj.filters
@@ -2949,6 +2949,9 @@
     <ClInclude Include="src\mcal\am6254_soc\mcal_osc.h">
       <Filter>src\mcal\am6254_soc</Filter>
     </ClInclude>
+    <ClInclude Include="src\util\utility\util_attribute.h">
+      <Filter>src\util\utility</Filter>
+    </ClInclude>
   </ItemGroup>
   <ItemGroup>
     <None Include="src\util\STL\algorithm">
diff --git a/ref_app/src/app/benchmark/app_benchmark.h b/ref_app/src/app/benchmark/app_benchmark.h
index 6e5118049..faadfbe01 100644
--- a/ref_app/src/app/benchmark/app_benchmark.h
+++ b/ref_app/src/app/benchmark/app_benchmark.h
@@ -8,15 +8,7 @@
 #ifndef APP_BENCHMARK_2018_10_02_H
   #define APP_BENCHMARK_2018_10_02_H
 
-  #if defined(ATTRIBUTE)
-  #undef ATTRIBUTE
-  #endif
-
-  #if defined(_MSC_VER)
-  #define ATTRIBUTE(a)
-  #else
-  #define ATTRIBUTE(a) __attribute__((a))
-  #endif
+  #include <util/utility/util_attribute.h>
 
   #define APP_BENCHMARK_TYPE_NONE                                0
   #define APP_BENCHMARK_TYPE_COMPLEX                             1
diff --git a/ref_app/src/app/benchmark/readme.md b/ref_app/src/app/benchmark/readme.md
index eda6f7b0d..9405ea6b8 100644
--- a/ref_app/src/app/benchmark/readme.md
+++ b/ref_app/src/app/benchmark/readme.md
@@ -84,13 +84,13 @@ The benchmark used is a ${\sim}100$ decimal digit AGM $\pi$ calculation.
 | Target             |  runtime $[ms]$ |  relative  |
 |--------------------|-----------------|------------|
 | `am6254_soc_`      |  0.37           |    1.0     |
-| `am335x`           |  1.5            |    4.0     |
+| `am335x`           |  1.5            |    4.1     |
 | `stm32f446`        |  5.1            |    14      |
 | `rpi_pico2_rp2350` |  6.3            |    17      |
 | `wch_ch32v307`     |  8.0            |    22      |
 | `xtensa_esp32_s3`  |  9.1            |    25      |
 | `rpi_pico_rp2040`  |  19             |    51      |
-| `avr`              |  420            |    760     |
+| `avr`              |  410            |   1100     |
 
 There are strikingly differing performance classes
 for the $8$-bit MICROCHIP(R) AVR controller of the ARDUINO
diff --git a/ref_app/src/app/led/app_led.cpp b/ref_app/src/app/led/app_led.cpp
index 05ba08d50..d09656122 100644
--- a/ref_app/src/app/led/app_led.cpp
+++ b/ref_app/src/app/led/app_led.cpp
@@ -1,5 +1,5 @@
 ///////////////////////////////////////////////////////////////////////////////
-//  Copyright Christopher Kormanyos 2007 - 2024.
+//  Copyright Christopher Kormanyos 2007 - 2025.
 //  Distributed under the Boost Software License,
 //  Version 1.0. (See accompanying file LICENSE_1_0.txt
 //  or copy at http://www.boost.org/LICENSE_1_0.txt)
diff --git a/ref_app/src/mcal/avr/mcal_gpt.cpp b/ref_app/src/mcal/avr/mcal_gpt.cpp
index 7ce1c1164..8540d6483 100644
--- a/ref_app/src/mcal/avr/mcal_gpt.cpp
+++ b/ref_app/src/mcal/avr/mcal_gpt.cpp
@@ -1,5 +1,5 @@
 ///////////////////////////////////////////////////////////////////////////////
-//  Copyright Christopher Kormanyos 2007 - 2024.
+//  Copyright Christopher Kormanyos 2007 - 2025.
 //  Distributed under the Boost Software License,
 //  Version 1.0. (See accompanying file LICENSE_1_0.txt
 //  or copy at http://www.boost.org/LICENSE_1_0.txt)
@@ -8,12 +8,14 @@
 #include <mcal_gpt.h>
 #include <mcal_reg.h>
 
+#include <util/utility/util_attribute.h>
+
 namespace
 {
   // The one (and only one) system tick.
   volatile auto mcal_gpt_system_tick = mcal::gpt::value_type { };
 
-  auto gpt_is_initialized() -> bool& __attribute__((used, noinline));
+  auto gpt_is_initialized() -> bool& ATTRIBUTE(used, noinline);
 
   auto gpt_is_initialized() -> bool&
   {
@@ -24,7 +26,7 @@ namespace
 }
 
 extern "C"
-auto __vector_16() -> void __attribute__((signal, used, externally_visible));
+auto __vector_16() -> void ATTRIBUTE(signal, used, externally_visible);
 
 auto __vector_16() -> void
 {
diff --git a/ref_app/src/mcal/avr/mcal_wdg.h b/ref_app/src/mcal/avr/mcal_wdg.h
index 23a37e965..d34bbcbfe 100644
--- a/ref_app/src/mcal/avr/mcal_wdg.h
+++ b/ref_app/src/mcal/avr/mcal_wdg.h
@@ -1,5 +1,5 @@
 ///////////////////////////////////////////////////////////////////////////////
-//  Copyright Christopher Kormanyos 2007 - 2024.
+//  Copyright Christopher Kormanyos 2007 - 2025.
 //  Distributed under the Boost Software License,
 //  Version 1.0. (See accompanying file LICENSE_1_0.txt
 //  or copy at http://www.boost.org/LICENSE_1_0.txt)
@@ -8,7 +8,9 @@
 #ifndef MCAL_WDT_2010_04_10_H
   #define MCAL_WDT_2010_04_10_H
 
-  extern "C" void __my_startup() __attribute__((section(".startup"), used, noinline));
+  #include <util/utility/util_attribute.h>
+
+  extern "C" void __my_startup() ATTRIBUTE(section(".startup"), used, noinline);
 
   namespace sys { namespace idle { auto task_func() -> void; } }
 
diff --git a/ref_app/src/os/os_cfg.h b/ref_app/src/os/os_cfg.h
index 42d845af7..5cb4a64b0 100644
--- a/ref_app/src/os/os_cfg.h
+++ b/ref_app/src/os/os_cfg.h
@@ -1,5 +1,5 @@
 ///////////////////////////////////////////////////////////////////////////////
-//  Copyright Christopher Kormanyos 2007 - 2024.
+//  Copyright Christopher Kormanyos 2007 - 2025.
 //  Distributed under the Boost Software License,
 //  Version 1.0. (See accompanying file LICENSE_1_0.txt
 //  or copy at http://www.boost.org/LICENSE_1_0.txt)
@@ -92,11 +92,11 @@
     {                                                                                             \
       os::task_control_block(app::led::task_init,                                                 \
                              app::led::task_func,                                                 \
-                             os::timer_type::microseconds(UINT32_C(   4000)),                     \
+                             os::timer_type::microseconds(UINT32_C(   7000)),                     \
                              os::timer_type::microseconds(UINT32_C(      0))),                    \
       os::task_control_block(app::benchmark::task_init,                                           \
                              app::benchmark::task_func,                                           \
-                             os::timer_type::microseconds(UINT32_C( 750000)),                     \
+                             os::timer_type::microseconds(UINT32_C( 830000)),                     \
                              os::timer_type::microseconds(UINT32_C(    379))),                    \
       os::task_control_block(sys::mon::task_init,                                                 \
                              sys::mon::task_func,                                                 \
diff --git a/ref_app/src/sys/start/sys_start.cpp b/ref_app/src/sys/start/sys_start.cpp
index 7fb66a3f3..4ac3c5e85 100644
--- a/ref_app/src/sys/start/sys_start.cpp
+++ b/ref_app/src/sys/start/sys_start.cpp
@@ -8,14 +8,10 @@
 #include <mcal/mcal.h>
 #include <os/os.h>
 
-#if defined(_MSC_VER)
-#define ATTRIBUTE(a)
-#else
-#define ATTRIBUTE(a) __attribute__((a))
-#endif
+#include <util/utility/util_attribute.h>
 
 #if (defined(__XTENSA__) && !defined(CONFIG_IDF_TARGET_ESP32S3))
-extern "C" ATTRIBUTE(used) auto app_main_loop() -> int;
+extern "C" auto app_main_loop() -> int ATTRIBUTE(used);
 #else
 ATTRIBUTE(used) auto main() -> int;
 #endif
diff --git a/ref_app/src/util/utility/util_attribute.h b/ref_app/src/util/utility/util_attribute.h
new file mode 100644
index 000000000..34175b3be
--- /dev/null
+++ b/ref_app/src/util/utility/util_attribute.h
@@ -0,0 +1,21 @@
+///////////////////////////////////////////////////////////////////////////////
+//  Copyright Christopher Kormanyos 2025.
+//  Distributed under the Boost Software License,
+//  Version 1.0. (See accompanying file LICENSE_1_0.txt
+//  or copy at http://www.boost.org/LICENSE_1_0.txt)
+//
+
+#ifndef UTIL_ATTRIBUTE_2025_08_09_H
+  #define UTIL_ATTRIBUTE_2025_08_09_H
+
+  #if defined(ATTRIBUTE)
+  #undef ATTRIBUTE
+  #endif
+
+  #if defined(_MSC_VER)
+    #define ATTRIBUTE(...)
+  #else
+    #define ATTRIBUTE(...) __attribute__((__VA_ARGS__))
+  #endif
+
+#endif // UTIL_ATTRIBUTE_2025_08_09_H
diff --git a/ref_app/target/micros/am6254_soc/Code/Appli/Core/a53/main.c b/ref_app/target/micros/am6254_soc/Code/Appli/Core/a53/main.c
index 492b4d990..38e500cf4 100644
--- a/ref_app/target/micros/am6254_soc/Code/Appli/Core/a53/main.c
+++ b/ref_app/target/micros/am6254_soc/Code/Appli/Core/a53/main.c
@@ -10,18 +10,14 @@
 #include <mcal_cpu.h>
 #include <mcal_irq.h>
 
+#include <util/utility/util_attribute.h>
+
 #include <stdbool.h>
 #include <stdint.h>
 
-#if defined(__GNUC__)
-#define ATTRIBUTE_USED __attribute__((used))
-#else
-#define ATTRIBUTE_USED
-#endif
-
 extern uint32_t GetActiveCoreId(void);
 
-extern ATTRIBUTE_USED int main(void);
+extern int main(void) ATTRIBUTE(used);
 
 //extern void main_core0(void);
 extern void main_core1(void);
@@ -29,9 +25,9 @@ extern void main_core2(void);
 extern void main_core3(void);
 extern void main_core0_init(void);
 
-ATTRIBUTE_USED void timer_isr(void);
-ATTRIBUTE_USED void main_x(void);
-ATTRIBUTE_USED static void main_init(const uint32_t ActiveCore);
+void timer_isr(void) ATTRIBUTE(used);
+void main_x(void) ATTRIBUTE(used);
+static void main_init(const uint32_t ActiveCore) ATTRIBUTE(used);
 
 void main_x(void)
 {
diff --git a/ref_app/target/micros/am6254_soc/Code/Startup/Core/a53/Startup.c b/ref_app/target/micros/am6254_soc/Code/Startup/Core/a53/Startup.c
index 91056f1fa..7874c261d 100644
--- a/ref_app/target/micros/am6254_soc/Code/Startup/Core/a53/Startup.c
+++ b/ref_app/target/micros/am6254_soc/Code/Startup/Core/a53/Startup.c
@@ -22,6 +22,8 @@
 
 #include <mcal_cpu.h>
 
+#include <util/utility/util_attribute.h>
+
 #include <stdint.h>
 
 typedef struct
@@ -44,12 +46,6 @@ extern const runtimeCopyTable_t __RUNTIME_COPY_TABLE[];
 extern const runtimeClearTable_t __RUNTIME_CLEAR_TABLE[];
 extern unsigned long __CTOR_LIST__[];
 
-#if defined(__GNUC__)
-#define ATTRIBUTE_USED __attribute__((used,noinline))
-#else
-#define ATTRIBUTE_USED
-#endif
-
 #define __STARTUP_RUNTIME_COPYTABLE   (runtimeCopyTable_t*)(&__RUNTIME_COPY_TABLE[0])
 #define __STARTUP_RUNTIME_CLEARTABLE  (runtimeClearTable_t*)(&__RUNTIME_CLEAR_TABLE[0])
 #define __STARTUP_RUNTIME_CTORS       (unsigned long*)(&__CTOR_LIST__[0])
@@ -65,7 +61,7 @@ static void Startup_Unexpected_Exit(void);
 static void Startup_InitSystemClock(void);
 static void Startup_InitSystemPeripheral(void);
 
-extern ATTRIBUTE_USED void main_x(void);
+extern void main_x(void) ATTRIBUTE(used);
 
 void Startup_Init(void)
 {
diff --git a/ref_app/target/micros/avr/make/avr.ld b/ref_app/target/micros/avr/make/avr.ld
index 6750717d3..afe3d031e 100644
--- a/ref_app/target/micros/avr/make/avr.ld
+++ b/ref_app/target/micros/avr/make/avr.ld
@@ -1,5 +1,5 @@
 /*
- Copyright Christopher Kormanyos 2007 - 2023.
+ Copyright Christopher Kormanyos 2007 - 2025.
  Distributed under the Boost Software License,
  Version 1.0. (See accompanying file LICENSE_1_0.txt
  or copy at http://www.boost.org/LICENSE_1_0.txt)
diff --git a/ref_app/target/micros/avr/make/avr_flags.gmk b/ref_app/target/micros/avr/make/avr_flags.gmk
index d22d7ee60..eff74bdb5 100644
--- a/ref_app/target/micros/avr/make/avr_flags.gmk
+++ b/ref_app/target/micros/avr/make/avr_flags.gmk
@@ -20,7 +20,7 @@ TGT_ALLFLAGS  = -O2
                 -mmcu=atmega328p                                                  \
                 -mrelax                                                           \
                 -finline-functions                                                \
-                -finline-limit=32                                                 \
+                -finline-limit=64                                                 \
                 -fsigned-char
 
 ifeq ($(TYP_OS),WIN)
@@ -30,8 +30,8 @@ TGT_ALLFLAGS := $(TGT_ALLFLAGS)
                 -mlong-double=64
 
 INC_PREFIX   := -isystem
-STD_C        := c23
-STD_CPP      := c++23
+STD_C        := c11
+STD_CPP      := c++20
 
 else
 
diff --git a/ref_app/target/micros/avr/startup/crt0.cpp b/ref_app/target/micros/avr/startup/crt0.cpp
index d5e67e1d8..8c941a55a 100644
--- a/ref_app/target/micros/avr/startup/crt0.cpp
+++ b/ref_app/target/micros/avr/startup/crt0.cpp
@@ -1,5 +1,5 @@
 ///////////////////////////////////////////////////////////////////////////////
-//  Copyright Christopher Kormanyos 2007 - 2021.
+//  Copyright Christopher Kormanyos 2007 - 2025.
 //  Distributed under the Boost Software License,
 //  Version 1.0. (See accompanying file LICENSE_1_0.txt
 //  or copy at http://www.boost.org/LICENSE_1_0.txt)
@@ -10,15 +10,17 @@
 
 #include <mcal/mcal.h>
 
+#include <util/utility/util_attribute.h>
+
 asm(".extern __initial_stack_pointer");
 
 namespace crt
 {
-  void init_ram  () __attribute__((section(".startup"), used, noinline));
-  void init_ctors() __attribute__((section(".startup"), used, noinline));
+  void init_ram  () ATTRIBUTE(section(".startup"), used, noinline);
+  void init_ctors() ATTRIBUTE(section(".startup"), used, noinline);
 }
 
-extern "C" void __my_startup() __attribute__((section(".startup"), used, noinline));
+extern "C" void __my_startup() ATTRIBUTE(section(".startup"), used, noinline);
 
 void __my_startup()
 {
diff --git a/ref_app/target/micros/avr/startup/crt0_init_ram.cpp b/ref_app/target/micros/avr/startup/crt0_init_ram.cpp
index 2a9e01edd..425d73560 100644
--- a/ref_app/target/micros/avr/startup/crt0_init_ram.cpp
+++ b/ref_app/target/micros/avr/startup/crt0_init_ram.cpp
@@ -1,16 +1,18 @@
 ///////////////////////////////////////////////////////////////////////////////
-//  Copyright Christopher Kormanyos 2007 - 2019.
+//  Copyright Christopher Kormanyos 2007 - 2025.
 //  Distributed under the Boost Software License,
 //  Version 1.0. (See accompanying file LICENSE_1_0.txt
 //  or copy at http://www.boost.org/LICENSE_1_0.txt)
 //
 
+#include <mcal_memory/mcal_memory_progmem_access.h>
+
+#include <util/utility/util_attribute.h>
+
 #include <algorithm>
 #include <cstddef>
 #include <cstdint>
 
-#include <mcal_memory/mcal_memory_progmem_access.h>
-
 extern "C"
 {
   extern mcal_progmem_uintptr_t _rom_data_begin;  // Start address for the initialization values of the rom-to-ram section.
@@ -22,7 +24,7 @@ extern "C"
 
 namespace crt
 {
-  void init_ram() __attribute__((section(".startup"), used, noinline));
+  void init_ram() ATTRIBUTE(section(".startup"), used, noinline);
 }
 
 void crt::init_ram()
diff --git a/ref_app/target/micros/avr/startup/crt1.cpp b/ref_app/target/micros/avr/startup/crt1.cpp
index bd0d52a2d..7a2f05706 100644
--- a/ref_app/target/micros/avr/startup/crt1.cpp
+++ b/ref_app/target/micros/avr/startup/crt1.cpp
@@ -1,5 +1,5 @@
 ///////////////////////////////////////////////////////////////////////////////
-//  Copyright Christopher Kormanyos 2007 - 2022.
+//  Copyright Christopher Kormanyos 2007 - 2025.
 //  Distributed under the Boost Software License,
 //  Version 1.0. (See accompanying file LICENSE_1_0.txt
 //  or copy at http://www.boost.org/LICENSE_1_0.txt)
@@ -8,6 +8,8 @@
 #include <cstdint>
 
 #include <mcal_memory/mcal_memory_progmem_access.h>
+
+#include <util/utility/util_attribute.h>
 #include <util/utility/util_utype_helper.h>
 
 extern "C"
@@ -28,7 +30,7 @@ extern "C"
 
 namespace crt
 {
-  void init_ctors() __attribute__((section(".startup"), used, noinline));
+  void init_ctors() ATTRIBUTE(section(".startup"), used, noinline);
 }
 
 void crt::init_ctors()
diff --git a/ref_app/target/micros/avr/startup/int_vect.cpp b/ref_app/target/micros/avr/startup/int_vect.cpp
index 6f7c0c315..176b1d789 100644
--- a/ref_app/target/micros/avr/startup/int_vect.cpp
+++ b/ref_app/target/micros/avr/startup/int_vect.cpp
@@ -1,18 +1,21 @@
 ///////////////////////////////////////////////////////////////////////////////
-//  Copyright Christopher Kormanyos 2007 - 2023.
+//  Copyright Christopher Kormanyos 2007 - 2025.
 //  Distributed under the Boost Software License,
 //  Version 1.0. (See accompanying file LICENSE_1_0.txt
 //  or copy at http://www.boost.org/LICENSE_1_0.txt)
 //
 
+#include <mcal_cpu.h>
+
+#include <util/utility/util_attribute.h>
+
 #include <array>
 #include <cstddef>
 #include <cstdint>
-#include <mcal_cpu.h>
 
-extern "C" void __my_startup       () __attribute__((section(".startup"), used, noinline));
-extern "C" void __vector_unused_irq() __attribute__((signal, used, externally_visible));
-extern "C" void __vector_16        () __attribute__((signal, used, externally_visible));
+extern "C" void __my_startup       () ATTRIBUTE(section(".startup"), used, noinline);
+extern "C" void __vector_unused_irq() ATTRIBUTE(signal, used, externally_visible);
+extern "C" void __vector_16        () ATTRIBUTE(signal, used, externally_visible);
 
 extern "C"
 void __vector_unused_irq()
@@ -39,7 +42,7 @@ namespace local
   using isr_vector_array_type = std::array<isr_type, count_of_isr_vector>;
 }
 
-const volatile local::isr_vector_array_type my_isr_vector __attribute__((section(".isr_vector"))) =
+const volatile local::isr_vector_array_type my_isr_vector ATTRIBUTE(section(".isr_vector")) =
 {{
                                                                                                                     // address   index   interrupt source
   { { static_cast<std::uint8_t>(UINT8_C(0x0C)), static_cast<std::uint8_t>(UINT8_C(0x94)) }, __my_startup },         // 0x00      0       reset
diff --git a/ref_app/target/micros/xtensa_esp32_s3_riscv_cop/startup/main.cpp b/ref_app/target/micros/xtensa_esp32_s3_riscv_cop/startup/main.cpp
index 408c039f1..985a51c6d 100644
--- a/ref_app/target/micros/xtensa_esp32_s3_riscv_cop/startup/main.cpp
+++ b/ref_app/target/micros/xtensa_esp32_s3_riscv_cop/startup/main.cpp
@@ -27,19 +27,11 @@
 #include <mcal_port.h>
 #include <mcal_pwm/mcal_pwm_port.h>
 
-#include <array>
-
-#if defined(ATTRIBUTE)
-#undef ATTRIBUTE
-#endif
+#include <util/utility/util_attribute.h>
 
-#if defined(_MSC_VER)
-#define ATTRIBUTE(a)
-#else
-#define ATTRIBUTE(a) __attribute__((a))
-#endif
+#include <array>
 
-ATTRIBUTE(used) auto main() -> int;
+auto main() -> int ATTRIBUTE(used);
 
 namespace
 {