diff --git a/Chapter04/bare/app/src/main.cpp b/Chapter04/bare/app/src/main.cpp
index e4d219b..666783b 100644
--- a/Chapter04/bare/app/src/main.cpp
+++ b/Chapter04/bare/app/src/main.cpp
@@ -4,7 +4,7 @@
 #include <uart_stm32.hpp>
 #include <stm32f072xb.h>
 
-extern "C" int main(void)
+int main()
 {
     hal::init();
 
diff --git a/Chapter05/gsm_lib/app/src/main.cpp b/Chapter05/gsm_lib/app/src/main.cpp
index 3b34a4a..d850cba 100644
--- a/Chapter05/gsm_lib/app/src/main.cpp
+++ b/Chapter05/gsm_lib/app/src/main.cpp
@@ -25,7 +25,7 @@ class gsm_lib{
 };
 
 
-extern "C" int main(void)
+int main()
 {
     hal::init();