6
我在創建Ruby擴展以導出C++庫時遇到問題，我在OSX下寫入了ruby。這個簡單的例子：無法創建C++ ruby擴展
#include <boost/regex.hpp>
extern "C" void Init_bayeux()
{
boost::regex expression("^(([^:/?#]+):)?(//([^/?#]*))?([^?#]*)(\\?([^#]*))?(#(.*))?");
}
導致bad_cast異常被拋出：
#0 0x00000001014663bd in __cxa_throw()
#1 0x00000001014cf6b2 in __cxa_bad_cast()
#2 0x00000001014986f9 in std::use_facet<std::collate<char> >()
#3 0x0000000101135a4f in boost::re_detail::cpp_regex_traits_base<char>::imbue (this=0x7fff5fbfe4d0, [email protected]) at cpp_regex_traits.hpp:218
#4 0x0000000101138d42 in cpp_regex_traits_base (this=0x7fff5fbfe4d0, [email protected]) at cpp_regex_traits.hpp:173
#5 0x000000010113eda6 in boost::re_detail::create_cpp_regex_traits<char> ([email protected]) at cpp_regex_traits.hpp:859
#6 0x0000000101149bee in cpp_regex_traits (this=0x101600200) at cpp_regex_traits.hpp:880
#7 0x0000000101142758 in regex_traits (this=0x101600200) at regex_traits.hpp:75
#8 0x000000010113d68c in regex_traits_wrapper (this=0x101600200) at regex_traits.hpp:169
#9 0x000000010113bae1 in regex_data (this=0x101600060) at basic_regex.hpp:166
#10 0x000000010113981e in basic_regex_implementation (this=0x101600060) at basic_regex.hpp:202
#11 0x0000000101136e1a in boost::basic_regex<char, boost::regex_traits<char, boost::cpp_regex_traits<char> > >::do_assign (this=0x7fff5fbfe710, p1=0x100540ae0 "^(([^:/?#]+):)?(//([^/?#]*))?([^?#]*)(\\?([^#]*))?(#(.*))?", p2=0x100540b19 "", f=0) at basic_regex.hpp:652
#12 0x0000000100540a66 in boost::basic_regex<char, boost::regex_traits<char, boost::cpp_regex_traits<char> > >::assign (this=0x7fff5fbfe710, p1=0x100540ae0 "^(([^:/?#]+):)?(//([^/?#]*))?([^?#]*)(\\?([^#]*))?(#(.*))?", p2=0x100540b19 "", f=0) at basic_regex.hpp:379
#13 0x0000000100540a13 in boost::basic_regex<char, boost::regex_traits<char, boost::cpp_regex_traits<char> > >::assign (this=0x7fff5fbfe710, p=0x100540ae0 "^(([^:/?#]+):)?(//([^/?#]*))?([^?#]*)(\\?([^#]*))?(#(.*))?", f=0) at basic_regex.hpp:364
#14 0x000000010054096e in basic_regex (this=0x7fff5fbfe710, p=0x100540ae0 "^(([^:/?#]+):)?(//([^/?#]*))?([^?#]*)(\\?([^#]*))?(#(.*))?", f=0) at basic_regex.hpp:333
#15 0x00000001005407e2 in Init_bayeux() at bayeux.cpp:10
#16 0x0000000100004593 in dln_load (file=0x1008bc000 "/Users/todi/sioux/lib/debug/rack/bayeux.bundle") at dln.c:1293
我編譯帶有擴展名：
g++ ./source/rack/bayeux.cpp -o /Users/todi/sioux/obj/debug/rack/bayeux.o -Wall -pedantic -Wno-parentheses -Wno-sign-compare -fno-common -c -pipe -I/Users/todi/sioux/source -ggdb -O0
最後又用鏈接的動態庫：
g++ -o /Users/todi/sioux/lib/debug/rack/bayeux.bundle -bundle -ggdb /Users/todi/sioux/obj/debug/rack/bayeux.o -L/Users/todi/sioux/lib/debug -lrack -lboost_regex-mt-d -lruby
我有s吸引了網絡並嘗試了各種鏈接和編譯器開關。如果我構建可執行文件，則不存在這樣的問題。其他人是否有這樣的問題並找到解決方案？
我進一步研究這一點，並發現導致異常的功能如下：
std::locale loc = std::locale("C");
std::use_facet< std::collate<char> >(loc);
性病源::整理<>我找到了扔statment：
use_facet(const locale& __loc)
{
const size_t __i = _Facet::id._M_id();
const locale::facet** __facets = __loc._M_impl->_M_facets;
if (__i >= __loc._M_impl->_M_facets_size || !__facets[__i])
__throw_bad_cast();
#ifdef __GXX_RTTI
return dynamic_cast<const _Facet&>(*__facets[__i]);
#else
return static_cast<const _Facet&>(*__facets[__i]);
#endif
}
這對你有意義嗎？
更新：我已經試過揚的建議：
Todis-MacBook-Pro:rack todi$ g++ -shared -fpic -o bayeux.bundle bayeux.cpp
Todis-MacBook-Pro:rack todi$ ruby -I. -rbayeux -e 'puts :ok'
terminate called after throwing an instance of 'std::bad_cast'
what(): std::bad_cast
Abort trap
版本：
Todis-MacBook-Pro:rack todi$ ruby -v
ruby 1.9.2p136 (2010-12-25 revision 30365) [x86_64-darwin10.6.0]
Todis-MacBook-Pro:rack todi$ gcc -v
Using built-in specs.
COLLECT_GCC=gcc
COLLECT_LTO_WRAPPER=/opt/local/libexec/gcc/x86_64-apple-darwin10/4.5.2/lto-wrapper
Target: x86_64-apple-darwin10
Configured with: ../gcc-4.5.2/configure --prefix=/opt/local --build=x86_64-apple-darwin10 --enable-languages=c,c++,objc,obj-c++,fortran,java --libdir=/opt/local/lib/gcc45 --includedir=/opt/local/include/gcc45 --infodir=/opt/local/share/info --mandir=/opt/local/share/man --datarootdir=/opt/local/share/gcc-4.5 --with-local-prefix=/opt/local --with-system-zlib --disable-nls --program-suffix=-mp-4.5 --with-gxx-include-dir=/opt/local/include/gcc45/c++/ --with-gmp=/opt/local --with-mpfr=/opt/local --with-mpc=/opt/local --enable-stage1-checking --disable-multilib --enable-fully-dynamic-string
Thread model: posix
gcc version 4.5.2 (GCC)
更新：
這不是約束檢查中拋出use_facet（），但下一行，這實際上是一個動態演員。這個例子歸結下來到或許真的與RTTI：
#define private public
#include <locale>
#include <iostream>
#include <typeinfo>
extern "C" void Init_bayeux()
{
std::locale loc = std::locale("C");
printf("size: %i\n", loc._M_impl->_M_facets_size);
printf("id: %i\n", std::collate<char>::id._M_id());
const std::locale::facet& fac = *loc._M_impl->_M_facets[ std::collate<char>::id._M_id() ];
printf("name: %s\n", typeid(fac).name());
printf("name: %s\n", typeid(std::collate<char>).name());
const std::type_info& a = typeid(fac);
const std::type_info& b = typeid(std::collate<char>);
printf("equal: %i\n", !a.before(b) && !b.before(a));
dynamic_cast< const std::collate<char>& >(fac);
}
我用的printf（），因爲COUT的使用也將失敗。上面的代碼的輸出是：
size: 28
id: 5
name: St7collateIcE
name: St7collateIcE
equal: 1
terminate called after throwing an instance of 'std::bad_cast'
what(): std::bad_cast
Abort trap
構建具有：
更新：
如果我重命名Init_bayeux到main（）和其鏈接到可執行文件，輸出是相同，但沒有呼叫終止。
更新：
當我寫一個小程序加載的共享庫，並執行Init_bayeux（），再次，沒有異常被拋出：
#include <dlfcn.h>
int main()
{
void* handle = dlopen("bayeux.bundle", RTLD_LAZY|RTLD_GLOBAL);
void(*f)(void) = (void(*)(void)) dlsym(handle, "Init_bayeux") ;
f();
}
所以在我看來，它可能是如何構建ruby.exe的問題。那有意義嗎？
更新： 我看了一下包含兩個type_info對象名稱的地址。相同的內容，但地址不同。我添加了-flat_namespace開關到鏈接命令。現在dynamic_cast的作品。 boost regex庫的原始問題仍然存在，但我認爲這可以通過將boost靜態鏈接到共享庫或通過使用-flat_namespace開關重建boost庫來解決。
更新： 現在我回來與提升正則表達式中的第一個例子中，建立與此命令：
g++ -shared -flat_namespace -fPIC -o bayeux.bundle /Users/todi/boost_1_49_0/stage/lib/libboost_regex.a bayeux.cpp
但加載擴展到Ruby解釋器的時候，靜態符號的初始化失敗：
ruby(59384,0x7fff712b8cc0) malloc: *** error for object 0x7fff70b19500: pointer being freed was not allocated
*** set a breakpoint in malloc_error_break to debug
Program received signal SIGABRT, Aborted.
0x00007fff8a6ab0b6 in __kill()
(gdb) bt
#0 0x00007fff8a6ab0b6 in __kill()
#1 0x00007fff8a74b9f6 in abort()
#2 0x00007fff8a663195 in free()
#3 0x0000000100541023 in boost::re_detail::cpp_regex_traits_char_layer<char>::init (this=0x10060be50) at basic_string.h:237
#4 0x0000000100543904 in boost::object_cache<boost::re_detail::cpp_regex_traits_base<char>, boost::re_detail::cpp_regex_traits_implementation<char> >::do_get ([email protected]) at cpp_regex_traits.hpp:366
#5 0x000000010056005b in create_cpp_regex_traits<char> (l=<value temporarily unavailable, due to optimizations>) at pending/object_cache.hpp:69
#6 0x0000000100544c33 in boost::basic_regex<char, boost::regex_traits<char, boost::cpp_regex_traits<char> > >::do_assign (this=0x7fff5fbfe090, p1=0x100567158 "^(([^:/?#]+):)?(//([^/?#]*))?([^?#]*)(\\?([^#]*))?(#(.*))?", p2=0x100567191 "", f=0) at cpp_regex_traits.hpp:880
#7 0x0000000100566280 in boost::basic_regex<char, boost::regex_traits<char, boost::cpp_regex_traits<char> > >::assign()
#8 0x000000010056622d in boost::basic_regex<char, boost::regex_traits<char, boost::cpp_regex_traits<char> > >::assign()
#9 0x0000000100566188 in boost::basic_regex<char, boost::regex_traits<char, boost::cpp_regex_traits<char> > >::basic_regex()
#10 0x0000000100566025 in Init_bayeux()
#11 0x0000000100003a23 in dln_load (file=0x10201a000 "/Users/todi/sioux/source/rack/bayeux.bundle") at dln.c:1293
#12 0x000000010016569d in vm_pop_frame [inlined]() at /Users/todi/.rvm/src/ruby-1.9.2-p320/vm_insnhelper.c:1465
#13 0x000000010016569d in rb_vm_call_cfunc (recv=4303980440, func=0x100042520 <load_ext>, arg=4303803000, blockptr=0x1, filename=<value temporarily unavailable, due to optimizations>, filepath=<value temporarily unavailable, due to optimizations>) at vm.c:1467
#14 0x0000000100043382 in rb_require_safe (fname=4303904640, safe=0) at load.c:602
#15 0x000000010017cbf3 in vm_call_cfunc [inlined]() at /Users/todi/.rvm/src/ruby-1.9.2-p320/vm_insnhelper.c:402
#16 0x000000010017cbf3 in vm_call_method (th=0x1003016b0, cfp=0x1004ffef8, num=1, blockptr=0x1, flag=8, id=<value temporarily unavailable, due to optimizations>, me=0x10182cfa0, recv=4303980440) at vm_insnhelper.c:528
...
再次，這不會失敗，當我從上面的小c程序加載共享庫。
更新： 現在我聯繫的第一個例子靜：
g++ -shared -fPIC -flat_namespace -nodefaultlibs -o bayeux.bundle -static -lstdc++ -lpthread -lgcc_eh -lboost_regex-mt bayeux.cpp
用了同樣的錯誤：
ruby(15197,0x7fff708aecc0) malloc: *** error for object 0x7fff7027e500: pointer being freed was not allocated
otool -L證實，每個庫鏈接靜態：
bayeux.bundle:
bayeux.bundle (compatibility version 0.0.0, current version 0.0.0)
/usr/lib/libSystem.B.dylib (compatibility version 1.0.0, current version 125.2.11)
debug：
如果我連接到boost調試版本，那麼它的工作方式與預期相同。
我無法重現您所描述的行爲。我用'g ++ -shared -fpic -o bayeux.so -lboost_regex bayeux.cpp'和'ruby -I編譯了示例C++文件。 -rbayeux -e'puts：ok''加載擴展沒有任何問題。但是，當我省略'-lboost_regex'時，我遇到了一些問題。此外，你能指定你使用的是哪個版本的Ruby和Boost，以及我們如何重現這個問題？ – Jan
@Jan，謝謝你試試。在OS X上，我必須將'so'擴展名更改爲'bundle'（否則require會找不到該庫），但結果仍然相同。 –
@Jan，你可以省略boost庫，沒有它就會失敗。這是對use_facet <>的調用失敗。 –