diff --git a/gdb/linespec.c b/gdb/linespec.c
index 50ebf6f..420ec15 100644
--- a/gdb/linespec.c
+++ b/gdb/linespec.c
@@ -341,10 +341,20 @@ iterate_name_matcher (const char *name, void *d)
   const struct symbol_matcher_data *data = d;
 
   if (data->symbol_name_match_p (name, data->lookup_name) == 0)
-    return 1;
-  return 0;
+    return 1; /* Expand this symbol's symbol table.  */
+  return 0; /* Skip this symbol.  */
 }
 
+/* Callback for iterate_over_all_matching_symtabs.  The callback
+   will be called once per matching symbol SYM, with DATA being
+   the argument of the same name that was passed to
+   iterate_over_all_matching_symtabs.  The callback should return
+   nonzero to indicate that iterate_over_all_matching_symtabs should
+   continue iterating, or zero to indicate that the iteration should
+   end.  */
+
+typedef int (symbol_found_callback_ftype) (struct symbol *sym, void *data);
+
 /* A helper that walks over all matching symtabs in all objfiles and
    calls CALLBACK for each symbol matching NAME.  If SEARCH_PSPACE is
    not NULL, then the search is restricted to just that program
@@ -353,7 +363,7 @@ iterate_name_matcher (const char *name, void *d)
 static void
 iterate_over_all_matching_symtabs (const char *name,
 				   const domain_enum domain,
-				   int (*callback) (struct symbol *, void *),
+				   symbol_found_callback_ftype callback,
 				   void *data,
 				   struct program_space *search_pspace)
 {
@@ -1808,14 +1818,14 @@ collect_one_symbol (struct symbol *sym, void *d)
   struct type *t;
 
   if (SYMBOL_CLASS (sym) != LOC_TYPEDEF)
-    return 1;
+    return 1; /* Continue iterating. */
 
   t = SYMBOL_TYPE (sym);
   CHECK_TYPEDEF (t);
   if (TYPE_CODE (t) != TYPE_CODE_STRUCT
       && TYPE_CODE (t) != TYPE_CODE_UNION
       && TYPE_CODE (t) != TYPE_CODE_NAMESPACE)
-    return 1;
+    return 1; /* Continue iterating. */
 
   slot = htab_find_slot (collector->unique_syms, sym, INSERT);
   if (!*slot)
@@ -1824,7 +1834,7 @@ collect_one_symbol (struct symbol *sym, void *d)
       VEC_safe_push (symbolp, collector->symbols, sym);
     }
 
-  return 1;
+  return 1; /* Continue iterating. */
 }
 
 /* Return the symbol corresponding to the substring of *ARGPTR ending
@@ -2215,7 +2225,7 @@ collect_function_symbols (struct symbol *sym, void *arg)
   if (SYMBOL_CLASS (sym) == LOC_BLOCK)
     VEC_safe_push (symbolp, *syms, sym);
 
-  return 1;
+  return 1; /* Continue iterating. */
 }
 
 /* Look up a function symbol in *ARGPTR.  If found, advance *ARGPTR
@@ -2722,7 +2732,7 @@ collect_symbols (struct symbol *sym, void *data)
     add_sal_to_sals (info->state, &info->result, &sal,
 		     SYMBOL_NATURAL_NAME (sym));
 
-  return 1;
+  return 1; /* Continue iterating. */
 }
 
 /* We've found a minimal symbol MSYMBOL to associate with our