Apple LLVM 4.1的STD链接器错误

Question

我在C++中有一个大型静态库,其中有一些Objective-C最初是为iOS(armv7)构建的.

我构建了一个OS X(64位Intel x86_64)版本,但是当我尝试在OS X应用程序项目中使用它(针对Lion 10.7)时,出现了数十个链接器错误,其中大部分都是关于标准库的符号.

我知道如何解决"我的"链接器问题,但下面复制的STD问题让我烦恼.

"std::basic_filebuf<char, std::char_traits<char> >::is_open() const"
"std::basic_stringbuf<char, std::char_traits<char>, std::allocator<char> >::str() const"
"std::basic_ios<char, std::char_traits<char> >::widen(char) const"
"std::istream& std::istream::_M_extract<double>(double&)"
"std::ostream::put(char)"
"std::ostream::flush()"
"std::ostream& std::ostream::_M_insert<void const*>(void const*)"
"std::ostream& std::ostream::_M_insert<bool>(bool)"
"std::ostream& std::ostream::_M_insert<double>(double)"
"std::ostream& std::ostream::_M_insert<unsigned long>(unsigned long)"
"std::ostream::operator<<(int)"
"std::ostream::operator<<(short)"
"std::string::_Rep::_M_destroy(std::allocator<char> const&)"
"std::string::_Rep::_S_terminal"
"std::string::_Rep::_S_empty_rep_storage"
"std::string::_Rep::_S_create(unsigned long, unsigned long, std::allocator<char> const&)"
"std::string::append(char const*, unsigned long)"
"std::string::append(std::string const&)"
"std::string::assign(std::string const&)"
"std::string::reserve(unsigned long)"
"std::basic_string<char, std::char_traits<char>, std::allocator<char> >::basic_string(char const*, std::allocator<char> const&)"
"std::basic_string<char, std::char_traits<char>, std::allocator<char> >::basic_string(std::string const&)"
"std::basic_string<char, std::char_traits<char>, std::allocator<char> >::~basic_string()"
"std::basic_ofstream<char, std::char_traits<char> >::open(char const*, std::_Ios_Openmode)"
"std::basic_ofstream<char, std::char_traits<char> >::close()"
"std::basic_ofstream<char, std::char_traits<char> >::basic_ofstream()"
"std::basic_ofstream<char, std::char_traits<char> >::~basic_ofstream()"
"std::_List_node_base::hook(std::_List_node_base*)"
"std::_List_node_base::unhook()"
"std::basic_stringstream<char, std::char_traits<char>, std::allocator<char> >::basic_stringstream(std::string const&, std::_Ios_Openmode)"
"std::basic_stringstream<char, std::char_traits<char>, std::allocator<char> >::basic_stringstream(std::_Ios_Openmode)"
"std::basic_stringstream<char, std::char_traits<char>, std::allocator<char> >::~basic_stringstream()"
"std::basic_ostringstream<char, std::char_traits<char>, std::allocator<char> >::basic_ostringstream(std::_Ios_Openmode)"
"std::basic_ostringstream<char, std::char_traits<char>, std::allocator<char> >::~basic_ostringstream()"
"std::ios_base::Init::Init()"
"std::ios_base::Init::~Init()"
"std::basic_ios<char, std::char_traits<char> >::clear(std::_Ios_Iostate)"
"std::basic_ostream<char, std::char_traits<char> >& std::__ostream_insert<char, std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*, long)"
"std::_Rb_tree_decrement(std::_Rb_tree_node_base*)"
"std::_Rb_tree_increment(std::_Rb_tree_node_base const*)"
"std::_Rb_tree_increment(std::_Rb_tree_node_base*)"
"std::__throw_logic_error(char const*)"
"std::__throw_length_error(char const*)"
"std::__throw_out_of_range(char const*)"
"std::_Rb_tree_rebalance_for_erase(std::_Rb_tree_node_base*, std::_Rb_tree_node_base&)"
"std::_Rb_tree_insert_and_rebalance(bool, std::_Rb_tree_node_base*, std::_Rb_tree_node_base*, std::_Rb_tree_node_base&)"
"std::cerr"
"std::cout"

我检查了我的构建设置,我的项目链接到标准库(-stdlib=libc++),我可以在main.cpp中使用std :: cout而没有任何问题.

我将构建设置中的编译器从Apple LLVM 4.1更改为LLVM GCC 4.2,问题消失了.我想继续使用Apple LLVM 4.1.我该如何解决这个问题？

谢谢!

Answer 1

在iOS 7中,我使用图表库并遇到同样的问题.在这种情况下,lib stdc ++不能解决问题.

我将stdc ++.6.dylib添加到我的构建阶段并找到符号.

Answer 2

更改链接使用的标准库libstdc++而不是libc++- 问题是其他库是使用g++使用libstdc++库的模式编译的.

请考虑以下示例代码:

dhcp-191:~/Development/testy/fred% cat fred.cpp
#include <iostream>
#include <string>
#include "fred.h"

using namespace std;

bool dofred(string &x)
{
    cout << x << endl;
    return true;
}
dhcp-191:~/Development/testy/fred% cat fred.h

#include <iostream>
#include <string>

bool dofred(std::string &x);

dhcp-191:~/Development/testy/fred% clang++ -stdlib=libc++ -shared -o fred.dylib fred.cpp
dhcp-191:~/Development/testy/fred% nm fred.dylib | c++filt | grep dofred
0000000000000fa0 T dofred(std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >&)
dhcp-191:~/Development/testy/fred% clang++ -stdlib=libstdc++ -shared -o fred.dylib fred.cpp
dhcp-191:~/Development/testy/fred% nm fred.dylib | c++filt | grep dofred                     
0000000000000e30 T dofred(std::string&)

您将获得两个完全不同的导出符号.尝试使用该符号时,使用相同-stdlib标志的应用程序将能够链接,而不会显示链接错误的应用程序.

Answer 3

将所有C++文件放入单独的库后,我遇到了这个问题.我确实将所有项目的设置设置为使用libc ++,但链接器不与libc ++链接.如果我将C++文件添加到主项目,问题就会消失.要解决此问题,您可以在主项目的"其他链接器标志"部分添加"-lc ++".这将迫使XCode链接到libc ++.

编辑:正如另一张海报所说,XCode可能表现正常.我曾经期望它知道添加C++链接,因为C++ lib源代码在同一个工作区.