diff --git a/src/header/time/mod.rs b/src/header/time/mod.rs
index 51d56b66ed..2d183ba78d 100644
--- a/src/header/time/mod.rs
+++ b/src/header/time/mod.rs
@@ -607,7 +607,7 @@ pub unsafe extern "C" fn timer_settime(
 ///
 /// See <https://pubs.opengroup.org/onlinepubs/9799919799/functions/timespec_get.html>.
 #[unsafe(no_mangle)]
-pub extern "C" fn timespec_get(tp: *mut timespec, base: c_int) -> c_int {
+pub unsafe extern "C" fn timespec_get(tp: *mut timespec, base: c_int) -> c_int {
     let tp = unsafe { Out::nonnull(tp) };
     Sys::clock_gettime(base - 1, tp).map(|()| base).unwrap_or(0)
 }
@@ -617,7 +617,8 @@ pub extern "C" fn timespec_get(tp: *mut timespec, base: c_int) -> c_int {
 /// The main differences are that this function:
 /// * returns `0` on error and `base` on success
 /// * only mandates TIME_UTC as a base
-pub extern "C" fn timespec_getres(res: *mut timespec, base: c_int) -> c_int {
+#[unsafe(no_mangle)]
+pub unsafe extern "C" fn timespec_getres(res: *mut timespec, base: c_int) -> c_int {
     let res = unsafe { Out::nullable(res) };
     Sys::clock_getres(base - 1, res).map(|()| base).unwrap_or(0)
 }