Inline throw() method in C++

I am trying to define a really simple exception class. Because it is so simple I want to keep it in the .h file only, but the compiler doesn't like throw(). The code:

#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 gives the following errors:

/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

for lines with throw(). Any idea how to fix it?

EDIT

I tried to remove the bodies of the problematic methods, i.e.

virtual ~PricingException() throw();// {}

And now I get even more weird error message:

/home/ga/dev/CppGroup/MonteCarlo/PricingExc开发者_StackOverfloweption.h:14: error: looser throw specifier for ‘virtual PricingException::~PricingException()’
/usr/include/c++/4.5/exception:65: error:   overriding ‘virtual std::exception::~exception() throw ()’

It just ignored my throw specifier!

Try the C++0x syntax instead, g++ 4.5 may be recent enough to support it:

const char* what() const noexcept { return msg.c_str(); }

However, this shouldn't matter (wording from draft 3242, section [except.spec]:

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 form throw(), noexcept, or noexcept(constant-expression) where the constant-expression yields true. A function with a non-throwing exception-specification does not allow any exceptions.

So try a newer build of g++, where these changes may be more completely implemented.

The closest I have found in the C++0x is:

15.4 Exception specifications [except.spec]

2 An exception-specification shall appear only on a function declarator for a function type, pointer to function type, reference to function type, or pointer to member function type that is the top-level type of a declaration or definition, or on such a type appearing as a parameter or return type in a function declarator.

It looks to me like it could disallow the use of exception specifications on definitions.

I wasn't able to reproduce this in several versions of g++. The most likely problem is that a previously included header file has a problem that's finally causing the compiler trouble when it sees the throw but not before.

Have you tried throw with out the ()? in this example (i know its in the .cpp file) but you see that the throws all do not have a parenthesis

http://www.glenmccl.com/eh_cmp.htm

Found it finally! @Mike Seymour was right in his comment - it turns out that in a file nr3.h (part of Numerical Recepies code) there is a macro throw(message) defined.

What I don't understand is why it impacts compilation of files that don't include this .h file...

Anyway, I think Visual Studio had a different compilation order or something, so it was pure luck that it compiled there and not under gcc.