#include <exception> #include <string> class PricingException : public virtual std::exception { private: std::string msg; public: PricingException(std::string message) : msg(message) {} const char* what() const throw() { return msg.c_str(); } ~PricingException() throw() {} };
GCC给出以下错误:
/home/ga/dev/CppGroup/MonteCarlo/PricingException.h:13: error: expected unqualified-id before ‘{’ token /home/ga/dev/CppGroup/MonteCarlo/PricingException.h:14: error: expected unqualified-id before ‘{’ token
对于带有throw()的行.知道怎么解决吗?
编辑
virtual ~PricingException() throw();// {}
现在我得到更奇怪的错误信息:
/home/ga/dev/CppGroup/MonteCarlo/PricingException.h:14: error: looser throw specifier for ‘virtual PricingException::~PricingException()’ /usr/include/c++/4.5/exception:65: error: overriding ‘virtual std::exception::~exception() throw ()’
它只是忽略了我的throw说明符!
解决方法
const char* what() const noexcept { return msg.c_str(); }
但是,这应该不重要(来自3242草案,[除了.spec]部分的措辞:
Two exception-specifications are compatible if:
- both are non-throwing (see below),regardless of their form,
- both have the form
noexcept(
constant-expression)
and the constant-expressions are equivalent,- one exception-specification is a noexcept-specification allowing all exceptions and the other is of the form
throw(
type-id-list)
,or- both are dynamic-exception-specifications that have the same set of adjusted types.
.
If a virtual function has an exception-specification,all declarations,including the definition,of any function that overrides that virtual function in any derived class shall only allow exceptions that are allowed by the exception-specification of the base class virtual function.
.
A function with no exception-specification or with an exception-specification of the form
noexcept(
constant-expression)
where the constant-expression yields false allows all exceptions. An exception-specification is
non-throwing if it is of the formthrow()
,noexcept
,ornoexcept(
constant-expression)
where the constant-expression yieldstrue
. A function with a non-throwing exception-specification does not allow any exceptions.
因此,尝试更新的g版本,这些更改可能会更完整地实现.