diff --git a/libs/binder/include/binder/IPCThreadState.h b/libs/binder/include/binder/IPCThreadState.h
index 4818889..b4e4a42 100644
--- a/libs/binder/include/binder/IPCThreadState.h
+++ b/libs/binder/include/binder/IPCThreadState.h
@@ -39,12 +39,28 @@
             
             status_t            clearLastError();
 
+            /**
+             * Returns the PID of the process which has made the current binder
+             * call. If not in a binder call, this will return getpid. If the
+             * call is oneway, this will return 0.
+             */
             pid_t               getCallingPid() const;
-            // nullptr if unavailable
-            //
-            // this can't be restored once it's cleared, and it does not return the
-            // context of the current process when not in a binder call.
+
+            /**
+             * Returns the SELinux security identifier of the process which has
+             * made the current binder call. If not in a binder call this will
+             * return nullptr. If this isn't requested with
+             * IBinder::setRequestingSid, it will also return nullptr.
+             *
+             * This can't be restored once it's cleared, and it does not return the
+             * context of the current process when not in a binder call.
+             */
             const char*         getCallingSid() const;
+
+            /**
+             * Returns the UID of the process which has made the current binder
+             * call. If not in a binder call, this will return 0.
+             */
             uid_t               getCallingUid() const;
 
             void                setStrictModePolicy(int32_t policy);