breakpoint and print at 387

(gdb) print Window->Application->Name
$4 = {<std::__1::__basic_string_common<true>> = {<No data fields>},
  __r_ = {<std::__1::__libcpp_compressed_pair_imp<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >::__rep, std::__1::allocator<char>, 2>> = {<std::__1::allocator<char>> = {<No data fields>}, __first_ = {{__l = {__cap_ = 29680635209667340, __size_ = 0,
            __data_ = 0x0}, __s = {{__size_ = 12 '\f', __lx = 12 '\f'},
            __data_ = "Safari", '\000' <repeats 16 times>}, __r = {__words = {29680635209667340,
              0, 0}}}}}, <No data fields>}, static npos = 18446744073709551615}

kwm backtrace

AXEvent_HotkeyPressed: Hotkey activated
KwmExecuteHotkey: Number of commands 1
KwmExecuteHotkey() space -fExperimental 7
AXEvent_SpaceChanged
CreateBSPTree() Create pair of leafs
CreateBSPTree() Create pair of leafs
AXEvent_WindowMoved: Safari - ax/commentary on ax.md at master · mnemnion/ax · GitHub
AXEvent_WindowMoved: Safari - Gmail
AXEvent_WindowMoved: Safari - Codesign gdb on Mac OS X Yosemite (10.10.2) — André Sabino
AXEvent_WindowResized: Safari - Codesign gdb on Mac OS X Yosemite (10.10.2) — André Sabino
AXEvent_WindowFocused: Safari - Codesign gdb on Mac OS X Yosemite (10.10.2) — André Sabino
AXEvent_WindowFocused: Safari - Codesign gdb on Mac OS X Yosemite (10.10.2) — André Sabino
AXEvent_ApplicationActivated: Safari
AXEvent_WindowFocused: Safari - Gmail
[New Thread 0x170b of process 29445]
[New Thread 0x1803 of process 29445]
[New Thread 0x1903 of process 29445]
[New Thread 0x1a03 of process 29445]

Thread 6 received signal SIGSEGV, Segmentation fault.
[Switching to Thread 0x170b of process 29445]
0x00007fff8af18152 in ?? () from /usr/lib/system/libsystem_c.dylib
(gdb) bt
#0  0x00007fff8af18152 in ?? () from /usr/lib/system/libsystem_c.dylib
#1  0x000070000029fea0 in ?? ()
#2  0x000000010000baf6 in std::__1::char_traits<char>::length (__s=0x0)
    at /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/string:640
#3  std::__1::operator<< <std::__1::char_traits<char> > (__os=..., __str=0x0)
    at /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../include/c++/v1/ostream:894
#4  Callback_AXEvent_WindowFocused (Event=<optimized out>) at kwm/window.cpp:387
Backtrace stopped: frame did not save the PC