libbinder_ndk: clarify descriptor encoding

These are utf-8 (same as is used by String8), though in practice they'll
generally be ASCII.

Bug: 185256226
Test: N/A
Change-Id: I73adfb5552bd7f81cdc9fd559f4edb3d922af67e

1 files changed, 4 insertions, 2 deletions

diff --git a/libs/binder/ndk/include_ndk/android/binder_ibinder.h b/libs/binder/ndk/include_ndk/android/binder_ibinder.h
index b9adc9a025..99908ca002 100644
--- a/libs/binder/ndk/include_ndk/android/binder_ibinder.h
+++ b/libs/binder/ndk/include_ndk/android/binder_ibinder.h
@@ -173,7 +173,7 @@ typedef binder_status_t (*AIBinder_Class_onTransact)(AIBinder* binder, transacti
  * Available since API level 29.
  *
  * \param interfaceDescriptor this is a unique identifier for the class. This is used internally for
- * sanity checks on transactions.
+ * validity checks on transactions. This should be utf-8.
  * \param onCreate see AIBinder_Class_onCreate.
  * \param onDestroy see AIBinder_Class_onDestroy.
  * \param onTransact see AIBinder_Class_onTransact.
@@ -645,7 +645,9 @@ binder_status_t AIBinder_setExtension(AIBinder* binder, AIBinder* ext) __INTRODU
  *
  * \return the class descriptor string. This pointer will never be null; a
  * descriptor is required to define a class. The pointer is owned by the class
- * and will remain valid as long as the class does.
+ * and will remain valid as long as the class does. For a local class, this will
+ * be the same value (not necessarily pointer equal) as is passed into
+ * AIBinder_Class_define. Format is utf-8.
  */
 const char* AIBinder_Class_getDescriptor(const AIBinder_Class* clazz) __INTRODUCED_IN(31);