Hi all.
The Solaris/SunOS lex generates C++ code with functions properly
wrapped into >extern "C"<, but only if:
- compiling as C++ (__cplusplus is #defined),
- the feature constant __EXTERN_C__ is #defined (probably meant just
for the SunOS compiler, not for all).
Other compilers, like GCC/G++, obviously miss the SunOS-specific
__EXTERN_C__ and thus miss >extern "C"<, declaring the yylex()
function as C++ (the default). This doesn't need to be a problem, but:
- the function should be declared as the user code expects it (as C
for C programs and as C++ for C++ programs),
- the Automake lex tests for C++ re-declare the function always as a C
function.
The re-declarations happens probably for good reason, like for lex
implementations which don't declare the function in advance combined
with C/C++ compilers which always require declarations. Unfortunately,
having the same function declared as C++ (default) first and then
later as C causes compiler errors.
The attached patch corrects the declarations in the following way:
- if we're in C++ mode and __EXTERN_C__ is declared (so, we're on a
SunOS with their compiler), declare the function as C in C++ mode
(i.e., use >extern "C"<), just like the SunOS lex does,
- if we're in C++ mode and __EXTERN_C__ is NOT declared, but also
"__sun" is not declared (so, we're NOT on a SunOS), still assume C++
mode, but a different system and declare the function as C in C++ mode
(i.e., use >extern "C"<) to support other compilers,
- if we're in C++ mode and __EXTERN_C__ is NOT declared, but also
"__sun" IS declared (so, we ARE on a SunOS, but not using their
compiler), declare the function as C++ in C++ mode, just like the
SunOS lex does,
- if we're NOT in C++ mode, declare the function as C. Not the case in
these tests, though.
This should match what the SunOS lex/compiler do and expect which
not braking other systems (re-checked on my Linux - works).
Verified that the defect exists on a Solaris 11.4 Build 15 (SunOS
5.11, GCC 7.3.0, amd64) and that the patch fixes it.
Furthermore, I checked how GCC manages the declarations of standard
C functions in C++. Seems so simple as saying:
using std::some_c_library_function_name;
which the SunOS library (or maybe just the old GCC library there) is
not doing.
So, it just takes this to fix the missing prototypes in C++ mode.
In short, the patch:
- fixes the remaining part of
https://debbugs.gnu.org/cgi/bugreport.cgi?bug=34151,
- fixes the remaining part of
https://debbugs.gnu.org/cgi/bugreport.cgi?bug=42393
(t/silent-many-languages.sh works for me),
- fixes https://debbugs.gnu.org/cgi/bugreport.cgi?bug=44795,
- fixes https://debbugs.gnu.org/cgi/bugreport.cgi?bug=49755,
- partially fixes https://debbugs.gnu.org/cgi/bugreport.cgi?bug=45205,
- partially fixes https://debbugs.gnu.org/cgi/bugreport.cgi?bug=55073.
Fortunately, these parts are just problems with the tests
themselves, not with Automake in general.
--
Regards - Bogdan ('bogdro') D. (GNU/Linux & FreeDOS)
X86 assembly (DOS, GNU/Linux): http://bogdro.evai.pl/index-en.php
Soft(EN): http://bogdro.evai.pl/soft http://bogdro.evai.pl/soft4asm
www.Xiph.org www.TorProject.org www.LibreOffice.org www.GnuPG.orgFrom b8813c99e220073b528511f47cc0c4cfd8ef1c20 Mon Sep 17 00:00:00 2001
From: Bogdan Drozdowski <>
Date: Sun, 16 Apr 2023 17:39:26 +0200
Subject: [PATCH] Fix lex/yacc C++ tests on SunOS
---
t/lex-clean-cxx.sh | 10 ++++++++--
t/lex-depend-cxx.sh | 5 ++++-
t/yacc-cxx.sh | 3 +++
t/yacc-d-cxx.sh | 3 +++
t/yacc-mix-c-cxx.sh | 3 +++
5 files changed, 21 insertions(+), 3 deletions(-)
diff --git a/t/lex-clean-cxx.sh b/t/lex-clean-cxx.sh
index 3632d5c87..afbacf392 100644
--- a/t/lex-clean-cxx.sh
+++ b/t/lex-clean-cxx.sh
@@ -54,7 +54,10 @@ END
cat > parsefoo.lxx << 'END'
%{
#define YY_DECL int yylex (void)
-extern "C" YY_DECL;
+#if (defined __cplusplus) && ((!defined __sun) || (defined __EXTERN_C__))
+extern "C"
+#endif
+YY_DECL;
#define YY_NO_UNISTD_H 1
int isatty (int fd) { return 0; }
%}
@@ -71,7 +74,10 @@ cp parsefoo.lxx parsebar.ll
cat > mainfoo.cc << 'END'
// This file should contain valid C++ but invalid C.
-extern "C" int yylex (void);
+#if (defined __cplusplus) && ((!defined __sun) || (defined __EXTERN_C__))
+extern "C"
+#endif
+int yylex (void);
using namespace std;
int main (int argc, char **argv)
{
diff --git a/t/lex-depend-cxx.sh b/t/lex-depend-cxx.sh
index 60615a54e..817450fc0 100644
--- a/t/lex-depend-cxx.sh
+++ b/t/lex-depend-cxx.sh
@@ -47,7 +47,10 @@ END
cat > joe.ll << 'END'
%{
#define YY_DECL int yylex (void)
-extern "C" YY_DECL;
+#if (defined __cplusplus) && ((!defined __sun) || (defined __EXTERN_C__))
+extern "C"
+#endif
+YY_DECL;
#define YY_NO_UNISTD_H 1
int isatty (int fd) { return 0; }
%}
diff --git a/t/yacc-cxx.sh b/t/yacc-cxx.sh
index 1bf75a975..5b385870c 100644
--- a/t/yacc-cxx.sh
+++ b/t/yacc-cxx.sh
@@ -49,6 +49,9 @@ cat > parse1.yy << 'END'
// Valid C++, but deliberately invalid C.
#include <cstdio>
#include <cstdlib>
+using std::exit;
+using std::free;
+using std::malloc;
// "std::" qualification required by Sun C++ 5.9.
int yylex (void) { return std::getchar (); }
void yyerror (const char *s) {}
diff --git a/t/yacc-d-cxx.sh b/t/yacc-d-cxx.sh
index 56f43c940..576e8e2aa 100644
--- a/t/yacc-d-cxx.sh
+++ b/t/yacc-d-cxx.sh
@@ -31,6 +31,9 @@ write_parse ()
#include <stdlib.h>
// Valid C++, but deliberately invalid C.
#include <cstdlib>
+ using std::exit;
+ using std::free;
+ using std::malloc;
#include "$header"
int yylex (void) { return 0; }
void yyerror (const char *s) {}
diff --git a/t/yacc-mix-c-cxx.sh b/t/yacc-mix-c-cxx.sh
index a73935c39..7c44e0926 100644
--- a/t/yacc-mix-c-cxx.sh
+++ b/t/yacc-mix-c-cxx.sh
@@ -86,6 +86,9 @@ cat > parse.yy <<'END'
// https://bugs.gnu.org/20031
#include <stdlib.h>
// Valid C++, but deliberately invalid C.
+using std::exit;
+using std::free;
+using std::malloc;
#include <cstdlib>
#include "parse.hh"
int yylex (void) { return 0; }
--
2.35.1
