diff --git a/libc/include/pthread.h b/libc/include/pthread.h
index 8b78a74..71ea8f9 100644
--- a/libc/include/pthread.h
+++ b/libc/include/pthread.h
@@ -314,17 +314,60 @@
 
 pthread_t pthread_self(void) __attribute_const__;
 
-#if defined(__USE_GNU)
-
-#if __BIONIC_AVAILABILITY_GUARD(26)
+#if __USE_GNU  && __BIONIC_AVAILABILITY_GUARD(26)
+/**
+ * [pthread_getname_np(3)](https://man7.org/linux/man-pages/man3/pthread_getname_np.3.html)
+ * gets the name of the given thread.
+ * Names are at most 16 bytes (including '\0').
+ *
+ * Returns 0 on success and returns an error number on failure.
+ *
+ * Available since API level 26.
+ */
 int pthread_getname_np(pthread_t __pthread, char* _Nonnull __buf, size_t __n) __INTRODUCED_IN(26);
-#endif /* __BIONIC_AVAILABILITY_GUARD(26) */
-
 #endif
-/* TODO: this should be __USE_GNU too. */
+
+/**
+ * [pthread_setname_np(3)](https://man7.org/linux/man-pages/man3/pthread_setname_np.3.html)
+ * sets the name of the given thread.
+ * Names are at most 16 bytes (including '\0').
+ * Truncation must be done by the caller;
+ * calls with longer names will fail with ERANGE.
+ *
+ * Returns 0 on success and returns an error number on failure.
+ *
+ * This should only have been available under _GNU_SOURCE,
+ * but is always available on Android by historical accident.
+ */
 int pthread_setname_np(pthread_t __pthread, const char* _Nonnull __name);
 
 /**
+ * [pthread_getaffinity_np(3)](https://man7.org/linux/man-pages/man3/pthread_getaffinity_np.3.html)
+ * gets the CPU affinity mask for the given thread.
+ *
+ * Returns 0 on success and returns an error number on failure.
+ *
+ * Available since API level 36.
+ * See sched_getaffinity() and pthread_gettid_np() for greater portability.
+ */
+#if __USE_GNU && __BIONIC_AVAILABILITY_GUARD(36)
+int pthread_getaffinity_np(pthread_t __pthread, size_t __cpu_set_size, cpu_set_t* __cpu_set) __INTRODUCED_IN(36);
+#endif
+
+/**
+ * [pthread_setaffinity_np(3)](https://man7.org/linux/man-pages/man3/pthread_setaffinity_np.3.html)
+ * sets the CPU affinity mask for the given thread.
+ *
+ * Returns 0 on success and returns an error number on failure.
+ *
+ * Available since API level 36.
+ * See sched_getaffinity() and pthread_gettid_np() for greater portability.
+ */
+#if __USE_GNU && __BIONIC_AVAILABILITY_GUARD(36)
+int pthread_setaffinity_np(pthread_t __pthread, size_t __cpu_set_size, const cpu_set_t* __cpu_set) __INTRODUCED_IN(36);
+#endif
+
+/**
  * [pthread_setschedparam(3)](https://man7.org/linux/man-pages/man3/pthread_setschedparam.3.html)
  * sets the scheduler policy and parameters of the given thread.
  *