I'm trying to use C++11 (with Clang and libc++ on OS X) for a program, but whenever I debug with gdb and try to inspect standard containers, gdb segfaults. Here's a minimal example:
file.cpp:
#include <iostream>
#include <string>
int main(int argc, char* argv[])
{
std::string str = "Hello world";
std::cout << str << std::endl; // Breakpoint here
}
If I compile for C++11 using the following:
$ c++ --version
Apple LLVM version 4.2 (clang-425.0.28) (based on LLVM 3.2svn)
Target: x86_64-apple-darwin12.4.0
Thread model: posix
$
$ c++ -ggdb -std=c++11 -stdlib=libc++ -Wall -pedantic -O0 -c file.cpp
$ c++ -ggdb -std=c++11 -stdlib=libc++ -Wall -pedantic -O0 file.o -o program
And then debug as follows, it crashes when I try to p str.size():
$ gdb program
GNU gdb 6.3.50-20050815 (Apple version gdb-1824) (Wed Feb 6 22:51:23 UTC 2013)
Copyright 2004 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB. Type "show warranty" for details.
This GDB was configured as "x86_64-apple-darwin"...Reading symbols for shared libraries ... done
(gdb) br file.cpp:8
Breakpoint 1 at 0x100000d80: file file.cpp, line 8.
(gdb) run
Starting program: /Users/mjbshaw/School/cs6640/2/program
Reading symbols for shared libraries ++............................. done
Breakpoint 1, main (argc=1, argv=0x7fff5fbffab0) at file.cpp:8
8 std::cout << str << std::endl; // Breakpoint here
(gdb) p str.size()
Program received signal EXC_BAD_ACCESS, Could not access memory.
Reason: KERN_INVALID_ADDRESS at address: 0x0000000000000000
std::__1::operator<< <char, std::__1::char_traits<char>, std::__1::allocator<char> > (__os=@0x7fff5fc3d628, __str=@0x1) at string:1243
1243
The program being debugged was signaled while in a function called from GDB.
GDB remains in the frame where the signal was received.
To change this behavior use "set unwindonsignal on"
Evaluation of the expression containing the function (std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >::__is_long() const) will be abandoned.
If I don't run this in gdb, I get no crash and it works fine (but I need gdb to debug my program). Also, if I remove -std=c++11 -stdlib=libc++ from the compiling options, then it works fine (even in gdb), but I need C++11 for my program.
Are there some known issues with gdb and C++11 (specifically libc++)? I know libc++ and libstdc++ can cause issues if used together, but I'm not trying to use them together (at least not consciously; all I want to use is libc++). Am I specifying some compilation options wrong? Is there a way to properly compile for C++11 on OS X and still be able to debug properly?
