diff --git a/example/mini_core.rs b/example/mini_core.rs
index bd7a4612a92c..5a4ee0a198ce 100644
--- a/example/mini_core.rs
+++ b/example/mini_core.rs
@@ -689,7 +689,7 @@ fn index(&self, index: usize) -> &Self::Output {
     }
 }
 
-extern {
+extern "C" {
     type VaListImpl;
 }
 
diff --git a/example/mini_core_hello_world.rs b/example/mini_core_hello_world.rs
index dcfa34cb729d..1d51e0a1856b 100644
--- a/example/mini_core_hello_world.rs
+++ b/example/mini_core_hello_world.rs
@@ -258,13 +258,13 @@ unsafe fn uninitialized<T>() -> T {
 
     assert_eq!(((|()| 42u8) as fn(()) -> u8)(()), 42);
 
-    extern {
+    extern "C" {
         #[linkage = "weak"]
         static ABC: *const u8;
     }
 
     {
-        extern {
+        extern "C" {
             #[linkage = "weak"]
             static ABC: *const u8;
         }
diff --git a/example/mod_bench.rs b/example/mod_bench.rs
index cae911c1073d..e8a9cade7474 100644
--- a/example/mod_bench.rs
+++ b/example/mod_bench.rs
@@ -3,7 +3,7 @@
 #![allow(internal_features)]
 
 #[link(name = "c")]
-extern {}
+extern "C" {}
 
 #[panic_handler]
 fn panic_handler(_: &core::panic::PanicInfo<'_>) -> ! {
diff --git a/example/std_example.rs b/example/std_example.rs
index 9e43b4635f0d..5fa1e0afb060 100644
--- a/example/std_example.rs
+++ b/example/std_example.rs
@@ -7,7 +7,7 @@
 use std::io::Write;
 use std::ops::Coroutine;
 
-extern {
+extern "C" {
     pub fn printf(format: *const i8, ...) -> i32;
 }