2007-01-30 Paolo Bonzini <bonzini@gnu.org>

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

diff --git a/src/flex-scanner.h b/src/flex-scanner.h
index bf190afd4f862551728ec79737d399ad04c2a375..5d08dec6a7bffa0b0d81b5089317dd239ae5b282 100644 (file)
--- a/src/flex-scanner.h
+++ b/src/flex-scanner.h
@@ -1,4 +1,4 @@
-/* Common parts between scan-code.l and scan-gram.l.
+/* Common parts between scan-code.l, scan-gram.l, and scan-skel.l.
 
    Copyright (C) 2006 Free Software Foundation, Inc.
 
@@ -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.
@@ -59,6 +72,8 @@ int   FLEX_PREFIX (lex_destroy) (void);
    STRING_FINISH also stores this string in LAST_STRING, which can be
    used, and which is used by STRING_FREE to free the last string.  */
 
+#ifndef FLEX_NO_OBSTACK
+
 static struct obstack obstack_for_string;
 
 #define STRING_GROW   \
@@ -72,3 +87,5 @@ static struct obstack obstack_for_string;
 
 #define STRING_FREE \
   obstack_free (&obstack_for_string, last_string)
+
+#endif