1

我正在使用提升 1.57。我需要在我未广泛使用的专有编译器中禁用异常支持。当我需要使用boost::smart_ptr时，以下步骤就像一个魅力：

  1. 使用以下user.hpp文件禁用 C++11 支持（使用 编译-DBOOST_USER_CONFIG="<user.hpp>"）：

    #define BOOST_HAS_NRVO
#define BOOST_NO_COMPLETE_VALUE_INITIALIZATION
#define BOOST_NO_CXX11_AUTO_DECLARATIONS
#define BOOST_NO_CXX11_AUTO_MULTIDECLARATIONS
#define BOOST_NO_CXX11_CHAR16_T
#define BOOST_NO_CXX11_CHAR32_T
#define BOOST_NO_CXX11_CONSTEXPR
#define BOOST_NO_CXX11_DECLTYPE
#define BOOST_NO_CXX11_DECLTYPE_N3276
#define BOOST_NO_CXX11_DEFAULTED_FUNCTIONS
#define BOOST_NO_CXX11_DELETED_FUNCTIONS
#define BOOST_NO_CXX11_EXPLICIT_CONVERSION_OPERATORS
#define BOOST_NO_CXX11_FINAL
#define BOOST_NO_CXX11_FUNCTION_TEMPLATE_DEFAULT_ARGS
#define BOOST_NO_CXX11_LAMBDAS
#define BOOST_NO_CXX11_LOCAL_CLASS_TEMPLATE_PARAMETERS
#define BOOST_NO_CXX11_NOEXCEPT
#define BOOST_NO_CXX11_NULLPTR
#define BOOST_NO_CXX11_RANGE_BASED_FOR
#define BOOST_NO_CXX11_RAW_LITERALS
#define BOOST_NO_CXX11_REF_QUALIFIERS
#define BOOST_NO_CXX11_RVALUE_REFERENCES
#define BOOST_NO_CXX11_SCOPED_ENUMS
#define BOOST_NO_CXX11_STATIC_ASSERT
#define BOOST_NO_CXX11_TEMPLATE_ALIASES
#define BOOST_NO_CXX11_UNICODE_LITERALS
#define BOOST_NO_CXX11_UNIFIED_INITIALIZATION_SYNTAX
#define BOOST_NO_CXX11_USER_DEFINED_LITERALS
#define BOOST_NO_CXX11_VARIADIC_MACROS
#define BOOST_NO_CXX11_VARIADIC_TEMPLATES
#define BOOST_NO_SFINAE_EXPR
#define BOOST_NO_TWO_PHASE_NAME_LOOKUP

  2. 通知 boost 库不要使用异常：-DBOOST_NO_EXCEPTIONS -DBOOST_EXCEPTION_DISABLE

  3. 导致以下编译行：MyCOMPILER -DBOOST_USER_CONFIG="<user.hpp>" -DBOOST_NO_EXCEPTIONS -DBOOST_EXCEPTION_DISABLE -c Foo.cpp -o Foo.o

那么下面这段代码就编译成功了：

#include <iostream>
#include <string>
#include <boost/shared_ptr.hpp>
#include <boost/smart_ptr/make_shared.hpp>

namespace boost {
    void throw_exception(std::exception const& e) {
        std::cerr << "Fake exception: " << e.what() << "\n";
        std::exit(255);
    }
}

class Foo {
  private:
    boost::shared_ptr<int> ptr;
  public:
    bool bar(const std::string file_name) {
      ptr = boost::make_shared<int>();
      return true;
    }
};

但是当我尝试将上述方法与以下源代码一起使用时，编译出错了：

#include <iostream>
#include <string>
#include <boost/property_tree/ptree.hpp>
#include <boost/property_tree/ini_parser.hpp>

namespace boost {
    void throw_exception(std::exception const& e) {
        std::cerr << "Fake exception: " << e.what() << "\n";
        std::exit(255);
    }
}

class Foo {
    public:
      bool bar(const std::string file_name) {   
        boost::property_tree::ptree prop_tree;
        boost::property_tree::read_ini(file_name, prop_tree);

        return !prop_tree.empty();
      }
};

例如导致以下错误：

"boost\boost/optional/optional.hpp", line 1047: Error:  #312: no suitable user-defined conversion from "boost::bad_optional_access" to "const std::exception" exists
            throw_exception(bad_optional_access());
                            ^
"boost\boost/optional/optional.hpp", line 1055: Error:  #312: no suitable user-defined conversion from "boost::bad_optional_access" to "const std::exception" exists
            throw_exception(bad_optional_access());
                            ^
"boost\boost/type_index/stl_type_index.hpp", line 138: Error:  #312: no suitable user-defined conversion from "std::runtime_error" to "const std::exception" exists
          boost::throw_exception(std::runtime_error("Type name demangling failed"));
                                 ^
"boost\boost/property_tree/ini_parser.hpp", line 168: Error:  #540: support for exception handling is disabled; use --exceptions to enable
          try {
          ^

最后的问题：

为什么在第一种情况下一切正常，但在第二种情况下不行？如何boost::property_tree在没有异常支持的情况下正确编译？这甚至可能吗？

4

0 回答 0