diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index 0b8651ccef..90e8d7a5c6 100644
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,8 @@
+2018-11-23  Pedro Alves  <palves@redhat.com>
+
+	* gdbthread.h (enum thread_state): Move comments here.
+	(is_running, is_stopped, is_exited): Remove declarations.
+
 2018-11-22  Pedro Alves  <palves@redhat.com>
 
 	* Makefile.in (COMMON_SFILES): Add thread-iter.c.
diff --git a/gdb/gdbthread.h b/gdb/gdbthread.h
index 94fc1b7472..2e8f4f195e 100644
--- a/gdb/gdbthread.h
+++ b/gdb/gdbthread.h
@@ -36,11 +36,32 @@ struct symtab;
 struct inferior;
 
 /* Frontend view of the thread state.  Possible extensions: stepping,
-   finishing, until(ling),...  */
+   finishing, until(ling),...
+
+   NOTE: Since the thread state is not a boolean, most times, you do
+   not want to check it with negation.  If you really want to check if
+   the thread is stopped,
+
+    use (good):
+
+     if (tp->state == THREAD_STOPPED)
+
+    instead of (bad):
+
+     if (tp->state != THREAD_RUNNING)
+
+   The latter is also true for exited threads, most likely not what
+   you want.  */
 enum thread_state
 {
+  /* In the frontend's perpective, the thread is stopped.  */
   THREAD_STOPPED,
+
+  /* In the frontend's perpective, the thread is running.  */
   THREAD_RUNNING,
+
+  /* The thread is listed, but known to have exited.  We keep it
+     listed (but not visible) until it's safe to delete it.  */
   THREAD_EXITED,
 };
 
@@ -566,31 +587,6 @@ extern void set_running (ptid_t ptid, int running);
    observer is called with PTID as argument.  */
 extern void set_stop_requested (ptid_t ptid, int stop);
 
-/* NOTE: Since the thread state is not a boolean, most times, you do
-   not want to check it with negation.  If you really want to check if
-   the thread is stopped,
-
-    use (good):
-
-     if (is_stopped (ptid))
-
-    instead of (bad):
-
-     if (!is_running (ptid))
-
-   The latter also returns true on exited threads, most likelly not
-   what you want.  */
-
-/* Reports if in the frontend's perpective, thread PTID is running.  */
-extern int is_running (ptid_t ptid);
-
-/* Is this thread listed, but known to have exited?  We keep it listed
-   (but not visible) until it's safe to delete.  */
-extern int is_exited (ptid_t ptid);
-
-/* In the frontend's perpective, is this thread stopped?  */
-extern int is_stopped (ptid_t ptid);
-
 /* Marks thread PTID as executing, or not.  If PTID is minus_one_ptid,
    marks all threads.