diff --git a/Include/code.h b/Include/code.h
index 0167ad4..cbf00d8 100644
--- a/Include/code.h
+++ b/Include/code.h
@@ -75,6 +75,9 @@
 PyAPI_FUNC(PyCodeObject *)
 PyCode_NewEmpty(const char *filename, const char *funcname, int firstlineno);
 
+/* Return the line number associated with the specified bytecode index
+   in this code object.  If you just need the line number of a frame,
+   use PyFrame_GetLineNumber() instead. */
 PyAPI_FUNC(int) PyCode_Addr2Line(PyCodeObject *, int);
 
 /* for internal use only */
diff --git a/Include/frameobject.h b/Include/frameobject.h
index 297b66d..17e7679 100644
--- a/Include/frameobject.h
+++ b/Include/frameobject.h
@@ -38,8 +38,11 @@
 
     PyThreadState *f_tstate;
     int f_lasti;		/* Last instruction if called */
-    /* As of 2.3 f_lineno is only valid when tracing is active (i.e. when
-       f_trace is set) -- at other times use PyCode_Addr2Line instead. */
+    /* Call PyFrame_GetLineNumber() instead of reading this field
+       directly.  As of 2.3 f_lineno is only valid when tracing is
+       active (i.e. when f_trace is set).  At other times we use
+       PyCode_Addr2Line to calculate the line from the current
+       bytecode index. */
     int f_lineno;		/* Current line number */
     int f_iblock;		/* index in f_blockstack */
     PyTryBlock f_blockstack[CO_MAXBLOCKS]; /* for try and loop blocks */
@@ -77,6 +80,9 @@
 
 PyAPI_FUNC(int) PyFrame_ClearFreeList(void);
 
+/* Return the line of code the frame is currently executing. */
+PyAPI_FUNC(int) PyFrame_GetLineNumber(PyFrameObject *);
+
 #ifdef __cplusplus
 }
 #endif