C++ template bugs in gcc 4.6
I've been working with gcc 4.6 with C++ doing some templates exercises
I seem to have some unexplained behavior which might be a bug, or maybe
I'm ignorant.
First - let me give you a link for my code
http://www.nylxs.com/docs/linklist.tgz
gcc version
ruben@www2:~> g++ -v
Using built-in specs.
COLLECT_GCC=g++
COLLECT_LTO_WRAPPER=/usr/lib/gcc/i586-suse-linux/4.6/lto-wrapper
Target: i586-suse-linux
Configured with: ../configure --prefix=/usr --infodir=/usr/share/info
--mandir=/usr/share/man --libdir=/usr/lib --libexecdir=/usr/lib
--enable-languages=c,c++,objc,fortran,obj-c++,java,ada
--enable-checking=release --with-gxx-include-dir=/usr/include/c++/4.6
--enable-ssp --disable-libssp --disable-plugin
--with-bugurl=http://bugs.opensuse.org/ --with-pkgversion='SUSE Linux'
--disable-libgcj --disable-libmudflap --with-slibdir=/lib
--with-system-zlib --enable-__cxa_atexit
--enable-libstdcxx-allocator=new --disable-libstdcxx-pch
--enable-version-specific-runtime-libs --program-suffix=-4.6
--enable-linux-futex --without-system-libunwind
--with-plugin-ld=/usr/bin/gold --with-arch-32=i586 --with-tune=generic
--build=i586-suse-linux
Thread model: posix
gcc version 4.6.0 20110415 [gcc-4_6-branch revision 172496] (SUSE Linux)
specifically, I wrote a program to test my templates that create a
linked list class. There is a simple library to do some statistics on the list
members. It is doing a double delete core dump in a section of code that
I see no reason for a destructor call. It didn't do this for a simpler
version of the template argument call.
ddd ./test_del2
test_del2.cpp:84
79 for( i=0; i < 100; ++i){
80 std::cout << "index " << i << "---
\n";
81 tally = new chainlist::List >;
82 stats::take_tally(a[i], tally );
83 std::cout << "Creating Tally " << std::endl;
84 tallies->insert(*tally);
85 std::cout << "inserted population figures for index " << i <<
"---\n";
86 delete tally;
87
88 //visual inspection of population data to make sure the resiults work
89 // std::cout << "visual inspection of population data to make sure
the results work" << std::endl;
breaking on line 84 and the stepping through
263 void List::insert ( T val )
264 {
265 if(!front()){
266 Node * tmp = new Node(val);
267 front(tmp);
268 endd(tmp);
269 cursor(tmp);
270 sizeup();
271 return;
272 }else{
273 Node * tmp = new Node(val, endd());
274 // endd()->next(tmp); // redundant
275 endd(tmp);
276 cursor(tmp);
277 sizeup();
278 return;
279 }
280 } /* --- end of method List::insert
/home/ruben/cplus/link_list_template_mysql/linklist.h:265
is the next line
on line 266 is where it seems to be doing weird stuff
home/ruben/cplus/link_list_template_mysql/linklist.h:266
it calls the correct constructor for the node object
/home/ruben/cplus/link_list_template_mysql/linklist.h:82
81 Node::Node(unk val, Node *item_to_link_to){
82 value(val);
83 if(!item_to_link_to){
84 next_ = 0;
85 }
86
87 else{
88 next(item_to_link_to->next());
89 item_to_link_to->next(this);
90 }
91 }
I the calls the accessory method value() from the list class
108 }
109
110 template
111 void Node::value(unk val){
112 value_ = new unk(val);
113 }
114
/home/ruben/cplus/link_list_template_mysql/linklist.h:112
it returns nomally
81 Node::Node(unk val, Node *item_to_link_to){
82 value(val);
83 if(!item_to_link_to){
84 next_ = 0;
85 }
86
87 else{
88 next(item_to_link_to->next());
89 item_to_link_to->next(this);
90 }
91 }
92 chainlist::Node > >::Node
(this=0x809f488, val=..., item_to_link_to=0x0) at
/home/ruben/cplus/link_list_template_mysql/linklist.h:83
then it calls for the List destructor, I have no idea way
373 template
374 List::~List(){
375 remove_all();
376 // std::cout << "Deleted All*" << __LINE__ << std::endl;
377 }
378
(gdb) ptype List
Type chainlist::List > has no component named
List.
(gdb) *** glibc detected ***
/home/ruben/cplus/link_list_template_mysql/test_del2: double free or
corruption (out): 0x0809f460 ***
=== Backtrace: =
/lib/libc.so.6[0xb7d9150b]
/lib/libc.so.6[0xb7d92de4]
/lib/libc.so.6(cfree+0x6d)[0xb7d95fdd]
/usr/lib/libstdc++.so.6(_ZdlPv+0x1f)[0xb7f7c87f]
/home/ruben/cplus/link_list_template_mysql/test_del2[0x804b4a4]
/home/ruben/cplus/link_list_template_mysql/test_del2[0x804b2c6]
/home/ruben/cplus/link_list_template_mysql/test_del2[0x804aa30]
/home/ruben/cplus/link_list_template_mysql/test_del2[0x804987d]
/home/ruben/cplus/link_list_template_mysql/test_del2[0x80498f0]
/home/ruben/cplus/link_list_template_mysql/test_del2[0x8048d42]
/lib/libc.so.6(__libc_start_main+0xfe)[0xb7d3aace]
/home/ruben/cplus/link_list_template_mysql/test_del2[0x8048961]
=== Memory map:
08048000-0804d000 r-xp 08:12 270203586
/home/ruben/cplus/link_list_template_mysql/test_del2
0804d000-0804e000 r--p 4000 08:12 270203586
/home/ruben/cplus/link_list_template_mysql/test_del2
0804e000-0804f000 rw-p 5000 08:12 270203586
/home/ruben/cplus/link_list_template_mysql/te
Re: C++ template bugs in gcc 4.6
On Sun, May 22, 2011 at 02:29:08PM +0100, Jonathan Wakely wrote: > re http://gcc.gnu.org/ml/gcc-bugs/2011-05/msg01899.html > > The gcc-bugs mailing list is for mails automatically generated by > bugzilla, if you want to report a bug please do so in bugzilla, not by > email. See http://gcc.gnu.org/bugs/ for instructions. > > If you want to ask for help using g++ then use the gcc-help mailing > list, see http://gcc.gnu.org/lists.html > Can't be done. It's not working, aside from the fact that this is too complex of an example to fit within the parameters. I spent nearly 45 minutes gathering all the information together. If the post is not adequate, that is fine. That's why i don't report bugs. > Thanks. -- http://www.mrbrklyn.com - Interesting Stuff http://www.nylxs.com - Leadership Development in Free Software So many immigrant groups have swept through our town that Brooklyn, like Atlantis, reaches mythological proportions in the mind of the world - RI Safir 1998 http://fairuse.nylxs.com DRM is THEFT - We are the STAKEHOLDERS - RI Safir 2002 "Yeah - I write Free Software...so SUE ME" "The tremendous problem we face is that we are becoming sharecroppers to our own cultural heritage -- we need the ability to participate in our own society." "> I'm an engineer. I choose the best tool for the job, politics be damned.< You must be a stupid engineer then, because politcs and technology have been attached at the hip since the 1st dynasty in Ancient Egypt. I guess you missed that one." © Copyright for the Digital Millennium
Re: C++ template bugs in gcc 4.6
On Sun, May 22, 2011 at 03:24:11PM +0100, Jonathan Wakely wrote: > On 22 May 2011 15:16, Ruben Safir wrote: > > On Sun, May 22, 2011 at 02:29:08PM +0100, Jonathan Wakely wrote: > >> re http://gcc.gnu.org/ml/gcc-bugs/2011-05/msg01899.html > >> > >> The gcc-bugs mailing list is for mails automatically generated by > >> bugzilla, if you want to report a bug please do so in bugzilla, not by > >> email. See http://gcc.gnu.org/bugs/ for instructions. > >> > >> If you want to ask for help using g++ then use the gcc-help mailing > >> list, see http://gcc.gnu.org/lists.html > >> > > > > > > Can't be done. It's not working, aside from the fact that this is too > > complex of an example to fit within the parameters. > > It's working fine for me. > well it doesn't for me. seens to not like my email address. > As for too complex: nonsense. Did you bother to read the link I provided? not interested in argueing...have other things I need to do. I'm sorry I made the report now. Easier to just code around the bug. Thanks for your time. > You can attach preprocessed source, though you should really try to > reduce it to a minimal testcase - I don't believe mysql++ is really > necessary to demonstrate the problem. > > None of that changes the fact gcc-bugs is the wrong list. > > > I spent nearly 45 minutes gathering all the information together. If > > the post is not adequate, that is fine. That's why i don't report bugs. > > Run your code under valgrind, it shows you were the first memory > corruption occurs. doing that, thanks > > If you don't want to report bugs then dont' be surprised if they don't > get fixed. nothing surprises me anymore...in more ways then most people can comprehend... The world sucks. Ruben -- http://www.mrbrklyn.com - Interesting Stuff http://www.nylxs.com - Leadership Development in Free Software So many immigrant groups have swept through our town that Brooklyn, like Atlantis, reaches mythological proportions in the mind of the world - RI Safir 1998 http://fairuse.nylxs.com DRM is THEFT - We are the STAKEHOLDERS - RI Safir 2002 "Yeah - I write Free Software...so SUE ME" "The tremendous problem we face is that we are becoming sharecroppers to our own cultural heritage -- we need the ability to participate in our own society." "> I'm an engineer. I choose the best tool for the job, politics be damned.< You must be a stupid engineer then, because politcs and technology have been attached at the hip since the 1st dynasty in Ancient Egypt. I guess you missed that one." © Copyright for the Digital Millennium
