diff --git a/libc/include/pthread.h b/libc/include/pthread.h
index 46898d6..3089adc 100644
--- a/libc/include/pthread.h
+++ b/libc/include/pthread.h
@@ -97,7 +97,7 @@
 int pthread_attr_destroy(pthread_attr_t* __attr);
 int pthread_attr_getdetachstate(const pthread_attr_t* __attr, int* __state);
 int pthread_attr_getguardsize(const pthread_attr_t* __attr, size_t* __size);
-int pthread_attr_getinheritsched(const pthread_attr_t* __attr, int* __flag);
+int pthread_attr_getinheritsched(const pthread_attr_t* __attr, int* __flag) __INTRODUCED_IN(28);
 int pthread_attr_getschedparam(const pthread_attr_t* __attr, struct sched_param* __param);
 int pthread_attr_getschedpolicy(const pthread_attr_t* __attr, int* __policy);
 int pthread_attr_getscope(const pthread_attr_t* __attr, int* __scope);
@@ -106,7 +106,7 @@
 int pthread_attr_init(pthread_attr_t* __attr);
 int pthread_attr_setdetachstate(pthread_attr_t* __attr, int __state);
 int pthread_attr_setguardsize(pthread_attr_t* __attr, size_t __size);
-int pthread_attr_setinheritsched(pthread_attr_t* __attr, int __flag);
+int pthread_attr_setinheritsched(pthread_attr_t* __attr, int __flag) __INTRODUCED_IN(28);
 int pthread_attr_setschedparam(pthread_attr_t* __attr, const struct sched_param* __param);
 int pthread_attr_setschedpolicy(pthread_attr_t* __attr, int __policy);
 int pthread_attr_setscope(pthread_attr_t* __attr, int __scope);