diff --git a/.gitignore b/.gitignore
index 42bd8b3..05f2ace 100644
--- a/.gitignore
+++ b/.gitignore
@@ -6,4 +6,5 @@
 *.bin
 *.hex
 *.map
+*.DS_Store
 .idea
diff --git a/src/cppmain.cc b/src/cppmain.cc
index 16e2f4a..6b3f1f7 100644
--- a/src/cppmain.cc
+++ b/src/cppmain.cc
@@ -177,7 +177,7 @@ namespace Heck {
 // C Linkage (Bridging)
 // ----------------------------------------------------------------------------------------------
 
-void HAL_GPIO_EXTI_Callback(uint16_t GPIO_Pin)
+extern "C" void HAL_GPIO_EXTI_Callback(uint16_t GPIO_Pin)
 {
     if (GPIO_Pin == GPIO_PIN_0) {
         Heck::irq1_cb();
@@ -186,7 +186,7 @@ void HAL_GPIO_EXTI_Callback(uint16_t GPIO_Pin)
     }
 }
 
-void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef *htim)
+extern "C" void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef *htim)
 {
     if (htim->Instance == TIM2) {
         Heck::log(
@@ -210,17 +210,17 @@ void HAL_TIM_PeriodElapsedCallback(TIM_HandleTypeDef *htim)
 }
 
 
-void HAL_DAC_ConvCpltCallbackCh1(DAC_HandleTypeDef *hdac)
+extern "C" void HAL_DAC_ConvCpltCallbackCh1(DAC_HandleTypeDef *hdac)
 {
     Heck::dac_start_dma();
 }
 
-void heck_log(char *msg)
+extern "C" void heck_log(char *msg)
 {
     Heck::log(std::string(msg));
 }
 
-void heck_cppmain(void)
+extern "C" void heck_cppmain(void)
 {
     Heck::main();
 }
@@ -232,7 +232,7 @@ void heck_cppmain(void)
   * @param  line: assert_param error line source number
   * @retval None
   */
-void assert_failed(uint8_t *file, uint32_t line)
+extern "C" void assert_failed(uint8_t *file, uint32_t line)
 {
     /* User can add his own implementation to report the file name and line number,
      ex: printf("Wrong parameters value: file %s on line %d\r\n", file, line) */
@@ -242,7 +242,7 @@ void assert_failed(uint8_t *file, uint32_t line)
     heck_log(str);
 }
 
-void Error_Handler(void)
+extern "C" void Error_Handler(void)
 {
     heck_log("Error_Handler StR1keZ!");
     __disable_irq();
diff --git a/src/init.c b/src/init.c
index b808ec0..92ee854 100644
--- a/src/init.c
+++ b/src/init.c
@@ -292,4 +292,5 @@ void heck_init()
     rng_init();
     irq_init();
     dma_init();
+
 }