Re: [boost] [system] - system_error

From: Peter Dimov (pdimov_at_[hidden])
Date: 2006-06-29 15:54:23

Beman Dawes wrote:
> <Oliver.Kowalke_at_[hidden]> wrote in message
> news:5D4F031442F5CB489CF88277DDBACCDD054D060B_at_drsse401.eu.infineon.com...
>> Hi,
>> shouldn't system_error::const char * what() const contain throw ()?
>
> Good question. I don't know the answer. The standard (for
> std::exception, which is the eventual base class) says:
>
>    virtual const char* what() const throw();
>
> system_error::what catches exceptions, so it never throws.
>
> I afraid I still don't know the rule as to when you need to provide a
> throw() specifier rather than just documenting that a function never
> throws.

You can't relax an exception specification in an overrider, only tighten it, 
so yes, system_error::what() needs throw(). I believe that a conforming 
compiler will reject it without the throw() specification.