diff --git a/src/proto/textformat.pro b/src/proto/textformat.pro
index 7ed9428..6f358fa 100644
--- a/src/proto/textformat.pro
+++ b/src/proto/textformat.pro
@@ -2,7 +2,7 @@
 int has_format_option(int x);
 void internal_format(int textwidth, int second_indent, int flags, int format_only, int c);
 void auto_format(int trailblank, int prev_line);
-void check_auto_format(int);
+void check_auto_format(int end_insert);
 int comp_textwidth(int ff);
 void op_format(oparg_T *oap, int keep_cursor);
 void op_formatexpr(oparg_T *oap);