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https://github.com/westes/flex/issues/436
https://bugs.gentoo.org/705800
https://developers.redhat.com/blog/2019/04/22/implicit-function-declarations-flexs-use-of-reallocarray
https://github.com/westes/flex/commit/4b5111d9772b5c160340ca96f08d30d7f6db5cda
https://github.com/westes/flex/commit/24fd0551333e7eded87b64dd36062da3df2f6380
https://github.com/westes/flex/commit/0db9f8903a446e7026874be519b8dc55a471f014
https://github.com/westes/flex/commit/a17d79e9c722a6735b6d2a8f152287404f27df32
https://github.com/westes/flex/commit/4081efa0831b15d7e4e4255401c225ad8262426d
https://github.com/westes/flex/commit/1985bb3c7abed940e91ad816504ef08a18c3b7c1
From 4b5111d9772b5c160340ca96f08d30d7f6db5cda Mon Sep 17 00:00:00 2001
From: Explorer09 <explorer09@gmail.com>
Date: Mon, 4 Sep 2017 08:28:53 +0800
Subject: [PATCH] scanner: Include flexdef.h at %top block of scan.l
config.h may define macros that alter the API of the standard library
funtions, and so it should be included before any other standard
header, even before the skeleton's standard header inclusion.
For example: config.h may #define _GNU_SOURCE that would expose the
reallocarray() prototype from <stdlib.h> on glibc 2.26+ systems. If we
include <stdlib.h> before config.h, reallocarray() would not be
available for use in lex file since the second include doesn't help
due to header guard.
For now our config.h might `#define malloc rpl_malloc` -- this
substitution must work before including stdlib.h, or else the compiler
will complain about missing prototypes, and may result in incorrect
code in scan.l (gcc warning: return makes pointer from integer without
a cast [-Wint-conversion]).
Fixes #247.
--- a/src/scan.l
+++ b/src/scan.l
@@ -1,5 +1,11 @@
/* scan.l - scanner for flex input -*-C-*- */
+%top{
+/* flexdef.h includes config.h, which may contain macros that alter the API */
+/* of libc functions. Must include first before any libc header. */
+#include "flexdef.h"
+}
+
%{
/* Copyright (c) 1990 The Regents of the University of California. */
/* All rights reserved. */
@@ -32,7 +38,6 @@
/* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR */
/* PURPOSE. */
-#include "flexdef.h"
#include "parse.h"
extern bool tablesverify, tablesext;
extern int trlcontxt; /* Set in parse.y for each rule. */
From 24fd0551333e7eded87b64dd36062da3df2f6380 Mon Sep 17 00:00:00 2001
From: Explorer09 <explorer09@gmail.com>
Date: Mon, 4 Sep 2017 10:47:33 +0800
Subject: [PATCH] build: AC_USE_SYSTEM_EXTENSIONS in configure.ac.
This would, e.g. define _GNU_SOURCE in config.h, enabling the
reallocarray() prototype in glibc 2.26+ on Linux systems with that
version of glibc.
Fixes #241.
--- a/configure.ac
+++ b/configure.ac
@@ -25,8 +25,10 @@
# autoconf requirements and initialization
AC_INIT([the fast lexical analyser generator],[2.6.4],[flex-help@lists.sourceforge.net],[flex])
+AC_PREREQ([2.60])
AC_CONFIG_SRCDIR([src/scan.l])
AC_CONFIG_AUX_DIR([build-aux])
+AC_USE_SYSTEM_EXTENSIONS
LT_INIT
AM_INIT_AUTOMAKE([1.15 -Wno-portability foreign std-options dist-lzip parallel-tests subdir-objects])
AC_CONFIG_HEADER([src/config.h])
From 0db9f8903a446e7026874be519b8dc55a471f014 Mon Sep 17 00:00:00 2001
From: Lukasz Baj <l.baj@radytek.com>
Date: Fri, 22 Sep 2017 10:24:46 +0200
Subject: [PATCH] build: Remove custom reallocarray() declaration.
Use one from <stdlib.h> instead because that is more portable.
--- a/src/flexdef.h
+++ b/src/flexdef.h
@@ -631,10 +631,6 @@ extern int sectnum, nummt, hshcol, dfaeql, numeps, eps2, num_reallocs;
extern int tmpuses, totnst, peakpairs, numuniq, numdup, hshsave;
extern int num_backing_up, bol_needed;
-#ifndef HAVE_REALLOCARRAY
-void *reallocarray(void *, size_t, size_t);
-#endif
-
void *allocate_array(int, size_t);
void *reallocate_array(void *, int, size_t);
From a17d79e9c722a6735b6d2a8f152287404f27df32 Mon Sep 17 00:00:00 2001
From: Explorer09 <explorer09@gmail.com>
Date: Sat, 14 Oct 2017 00:36:54 +0800
Subject: [PATCH] scanner: Define _POSIX_C_SOURCE when needed in skeleton.
The function fileno() is defined by POSIX. When flex would otherwise not provide that feature macro, we define it.
Fixes #263
--- a/src/flex.skl
+++ b/src/flex.skl
@@ -218,6 +218,14 @@ m4_ifdef( [[M4_YY_TABLES_EXTERNAL]],
/* begin standard C headers. */
%if-c-only
+m4_ifdef( [[M4_YY_ALWAYS_INTERACTIVE]], ,
+[[m4_ifdef( [[M4_YY_NEVER_INTERACTIVE]], ,
+[[#ifndef _POSIX_C_SOURCE
+#define _POSIX_C_SOURCE 1 /* for fileno() */
+#ifndef _POSIX_SOURCE
+#define _POSIX_SOURCE 1
+#endif
+#endif]])]])
#include <stdio.h>
#include <string.h>
#include <errno.h>
From 4081efa0831b15d7e4e4255401c225ad8262426d Mon Sep 17 00:00:00 2001
From: Explorer09 <explorer09@gmail.com>
Date: Thu, 8 Mar 2018 10:04:36 +0800
Subject: [PATCH] scanner: Fix glibc features.h dependency in skeleton.
Commit a17d79e9c722a6735b6d2a8f152287404f27df32 defines _POSIX_C_SOURCE
to the minimum of 1 if it's not defined in the user's scanner code or
the compiling environment. However in glibc the macros are not yet set
up until one of the libc headers is included. This unfortunately have
made us overwrite the default _POSIX_C_SOURCE value that would be
defined by glibc (200809L at the time of writing), causing regressions
in user code.
Now in this patch:
1. Ensure feature test macros have been set up in glibc before checking
or defining any of them in our skeleton code.
2. Have a more conservative logic when determining the need to define
_POSIX_C_SOURCE (required for fileno()).
Fixes: #313
Note:
It could be tricky for application code to ensure feature test macros
have been set up in glibc, since <features.h> is no portable header and
not meant to be included directly by applications. The way to do it is
to include a libc header which in turn includes <features.h>. However,
many of the glibc headers check __USE_POSIX (a glibc internal macro
defined if _POSIX_C_SOURCE is defined) and determine which interfaces
to expose already, making the headers inappropriate for our goal.
Those which don't depend on _POSIX_C_SOURCE, and are also available
since ANSI C89, are only <assert.h>, <errno.h> and <math.h>.
<assert.h> is finally favored due to other considerations:
- <math.h> check for __USE_XOPEN in glibc, making a dependency on
_XOPEN_SOURCE, besides it exposes much more interfaces than we need.
- In djgpp, <errno.h> depends on _POSIX_SOURCE to hide definitions of
some errno values when it's defined.
- <assert.h> exposes the fewest interfaces among the 3 headers and, at
the time of writing, checks for only C99 (for __func__), C11 (for
_Static_assert), and _GNU_SOURCE when needed.
Signed-off-by: Kang-Che Sung <explorer09@gmail.com>
--- a/src/flex.skl
+++ b/src/flex.skl
@@ -220,11 +220,21 @@ m4_ifdef( [[M4_YY_TABLES_EXTERNAL]],
%if-c-only
m4_ifdef( [[M4_YY_ALWAYS_INTERACTIVE]], ,
[[m4_ifdef( [[M4_YY_NEVER_INTERACTIVE]], ,
-[[#ifndef _POSIX_C_SOURCE
-#define _POSIX_C_SOURCE 1 /* for fileno() */
-#ifndef _POSIX_SOURCE
-#define _POSIX_SOURCE 1
+[[/* Feature test macros. Flex uses functions that require a minimum set of
+ * macros defined. As defining some macros may hide function declarations that
+ * user code might use, be conservative and respect user's definitions as much
+ * as possible. In glibc, feature test macros may not be all set up until one
+ * of the libc header (that includes <features.h>) is included. This creates
+ * a circular dependency when we check the macros. <assert.h> is the safest
+ * header we can include and does not declare too many functions we don't need.
+ */
+#if !defined(__GNU_LIBRARY__) && defined(__STDC__)
+#include <assert.h>
#endif
+#if !(defined(_POSIX_C_SOURCE) || defined(_XOPEN_SOURCE) || \
+ defined(_POSIX_SOURCE))
+# define _POSIX_C_SOURCE 1 /* Required for fileno() */
+# define _POSIX_SOURCE 1
#endif]])]])
#include <stdio.h>
#include <string.h>
From 1985bb3c7abed940e91ad816504ef08a18c3b7c1 Mon Sep 17 00:00:00 2001
From: Explorer09 <explorer09@gmail.com>
Date: Thu, 8 Mar 2018 09:53:24 +0800
Subject: [PATCH] scanner: correct comments about __STDC_LIMIT_MACROS.
No code changes.
Signed-off-by: Kang-Che Sung <explorer09@gmail.com>
--- a/src/flexint.h
+++ b/src/flexint.h
@@ -7,8 +7,8 @@
#if defined (__STDC_VERSION__) && __STDC_VERSION__ >= 199901L
-/* C99 says to define __STDC_LIMIT_MACROS before including stdint.h,
- * if you want the limit (max/min) macros for int types.
+/* C++ systems might need __STDC_LIMIT_MACROS defined before including
+ * <stdint.h>, if you want the limit (max/min) macros for int types.
*/
#ifndef __STDC_LIMIT_MACROS
#define __STDC_LIMIT_MACROS 1
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