编译错误相关的提升

Question

当我使用 boost 1.52.1 和 gcc-4.7.1 编译我的代码时，出现以下错误。这似乎是 boost 和 c++ 库之间的冲突。 有人知道如何解决这个问题吗？

非常感谢您的回复。

c:\program files\mingw64\bin\../lib/gcc/x86_64-w64- 
mingw32/4.7.1/../../../../include/boost/math/policies
/error_handling.hpp: In function 'bool    boost::math::policies::
detail::check_overflow(std::complex<T>, 
R*, const char*, const Policy&)':c:\program    
files\mingw64\bin\../lib/gcc/x86_64-w64 mingw32/4.7.1
/../../../../include/boost/math/policies/error_handling.hpp:583:11: 
error: expected unqualified-id before numeric constant
c:\program files\mingw64\bin\../lib/gcc/x86_64-w64-mingw32
/4.7.1/../../../../include/boost/math/policies/error_handling.hpp:
584:49: error: lvalue required as unary '&' operand
 c:\program files\mingw64\bin\../lib/gcc/x86_64-w64-mingw32/4.7.1/
 ../../../../include/boost/math/policies/
 error_handling.hpp:584:107: error: 'im' was not declared in this
 scope c:\program files\mingw64\bin\../lib/gcc/x86_64-w64-mingw32
 /4.7.1/../../../../include/boost/math/policies/error_handling.
 hpp: In function 'bool boost::math::policies::detail::
 check_underflow(std::complex<T>, R*, const char*, const Policy&)':
 c:\program files\mingw64\bin\../lib/gcc/x86_64-w64-  mingw32
 /4.7.1/../../../../include/boost/math/policies
 /error_handling.hpp:602:11: error: expected unqualified-id before       
 numeric constant c:\program files\mingw64\bin\../lib/gcc/
 x86_64-w64 mingw32/4.7.1/../../../../include/boost/math/policies
 /error_handling.hpp:603:50: error: lvalue required as 
 unary '&' operand c:\program files\mingw64\bin\../lib/gcc/
 x86_64-w64 mingw32/4.7.1/../../../../include/boost/math/policies
 /error_handling .hpp:603:109: error: 'im' was not declared in 
 this scope c:\program files\mingw64\bin\../lib/gcc
 /x86_64-w64-mingw32/4.7.1/../../../../include/boost/math/policies/
 error_handling.hpp: In function 'bool boost::math::policies::
 detail::check_denorm(std::complex<T>, R*, const char*, 
  const Policy&)':c:\program files\mingw64\bin\../lib/gcc
 /x86_64-w64-mingw32/4.7.1/../../../../include/boost/
 math/policies/error_handling.hpp:622:11: error: expected 
 unqualified-id before numeric constant
 c:\program files\mingw64\bin\../lib/gcc/x86_64-w64-
 mingw32/4.7.1/../../../../include/boost/math/policies/
 error_handling.hpp:623:47: error: lvalue required as 
 unary '&' operand
 c:\program files\mingw64\bin\../lib/gcc/x86_64-w64-
 mingw32/4.7.1/../../../../include/boost/math/policies/
 error_handling.hpp:623:103: error: 'im' was not declared
 in this scope

错误出现在代码 boost\math\policy\error_handling.hpp 中。但我不确定程序何时引用这些函数。这个错误是怎么发生的？

template <class R, class T, class Policy>
inline bool check_overflow(std::complex<T> val, R* result, const
char* function, const Policy& pol)
{
    typedef typename R::value_type r_type;
    r_type re, im;
    bool r = check_overflow<r_type>(val.real(), &re, function, pol) || check_overflow<r_type>(val.imag(), &im, function, pol);
    *result = R(re, im);
    return r;
}

 template <class R, class T, class Policy>
 inline bool check_underflow(std::complex<T> val, R* result, const char* function, const Policy& pol)
{
     typedef typename R::value_type r_type;
     r_type re, im;
     bool r = check_underflow<r_type>(val.real(), &re, function, pol) || check_underflow<r_type>(val.imag(), &im, function, pol);
     *result = R(re, im);
     return r;
}

Answer 1

鉴于这两个函数和这个嘈杂的错误消息，我可以说用作参数 R 的类型没有定义 value_type。因此，未定义类型 r_type 和变量 im 和 re。结果你得到error: 'im' was not declared in this scope 错误。

仅使用提供的代码，我可以看到类型 R 具有以下要求：

• 必须定义类型value_type
• 它必须有构造函数R(value_type real, value_type imagine)

这意味着你使用了一些不正确地使用内部 check_underflow/check_overflow 函数的 boost 库，我猜是模板参数不兼容。