* NEWS (2.3a+): Mention yesterday's state-removal change.

[bison.git] / src / flex-scanner.h

diff --git a/src/flex-scanner.h b/src/flex-scanner.h
index 3e16234c553605ad52e47c05e6e7985ff75589f3..5d08dec6a7bffa0b0d81b5089317dd239ae5b282 100644 (file)
--- a/src/flex-scanner.h
+++ b/src/flex-scanner.h
@@ -50,6 +50,19 @@ int   FLEX_PREFIX (lex_destroy) (void);
 # define yytext  FLEX_PREFIX (text)
 #endif
 
+/* Non-reentrant scanners generated by Flex 2.5.9 and later (and some earlier
+   versions according to the Flex manual) leak memory if yylex_destroy is not
+   invoked.  However, yylex_destroy is not defined before Flex 2.5.9, so give
+   an implementation here that at least appears to work with Flex 2.5.4.  */
+#if !defined(YY_FLEX_MAJOR_VERSION) || YY_FLEX_MAJOR_VERSION < 2 \
+    || (YY_FLEX_MAJOR_VERSION == 2 \
+        && (!defined(YY_FLEX_MINOR_VERSION) || YY_FLEX_MINOR_VERSION < 5 \
+            || (YY_FLEX_MINOR_VERSION == 5 \
+                && (!defined(YY_FLEX_SUBMINOR_VERSION) \
+                    || YY_FLEX_SUBMINOR_VERSION < 9))))
+# define yylex_destroy() yy_delete_buffer (YY_CURRENT_BUFFER)
+#endif
+
 /* OBSTACK_FOR_STRING -- Used to store all the characters that we need to
    keep (to construct ID, STRINGS etc.).  Use the following macros to
    use it.