Document exp_descriptor.op_name should never return NULL.

This documents a constaint that struct exp_descriptor's "op_name"
method implementation should obey.  This might not have been part
of the initial design, but is currently true of all instantiations,
and already assumed by the current users.

gdb/ChangeLog:

        * parser-defs.h (struct exp_descriptor): Document constraint
        on return value for "op_name" callbacks.

diff --git a/gdb/ChangeLog b/gdb/ChangeLog
index b344cba..96c9cfa 100644 (file)
--- a/gdb/ChangeLog
+++ b/gdb/ChangeLog
@@ -1,3 +1,8 @@
+2012-10-19  Joel Brobecker  <brobecker@adacore.com>
+
+       * parser-defs.h (struct exp_descriptor): Document constraint
+       on return value for "op_name" callbacks.
+
 2012-10-18  Tom Tromey  <tromey@redhat.com>
 
        * tracepoint.c (print_one_static_tracepoint_marker): Constify.

diff --git a/gdb/parser-defs.h b/gdb/parser-defs.h
index 86f3bdf..c889d56 100644 (file)
--- a/gdb/parser-defs.h
+++ b/gdb/parser-defs.h
@@ -335,7 +335,10 @@ struct exp_descriptor
                                                void *data),
                           void *data);
 
-    /* Name of this operator for dumping purposes.  */
+    /* Name of this operator for dumping purposes.
+       The returned value should never be NULL, even if EXP_OPCODE is
+       an unknown opcode (a string containing an image of the numeric
+       value of the opcode can be returned, for instance).  */
     char *(*op_name) (enum exp_opcode);
 
     /* Dump the rest of this (prefix) expression after the operator