Of course, I didn't consider the problem of exception specifications. You'd have to do something fancy to work around that. Nick On Sun, Mar 28, 2010 at 1:38 PM, Nicholas Howe <nicholas.howe@gmail.com>wrote:
On Thu, Mar 25, 2010 at 6:58 PM, Tom Brinkman <reportbase2007@gmail.com>wrote:
1) Boost uses exceptions.
I'm a game programmer. I've worked at companies that disable exceptions. One advantage of exceptions is that when they occur, the stack is unwound and object destructors are executed. Another is that higher-level code is given an opportunity to recover from the exceptional condition. If you don't care about either of these things, it might be acceptable for your program to terminate at any point where it would normally throw an exception. Assuming your C++ implementation already terminates execution or otherwise behaves acceptably when features like std::operator new and reference dynamic_cast fail with exceptions disabled, I think you could achieve that with Boost using the preprocessor as shown below.
#ifndef THROW_H #define THROW_H
#include <cstdlib>
struct Throw { };
template< class T > inline void operator <<( Throw &, T const & ) { std::exit( EXIT_FAILURE ); }
#define throw Throw() <<
#endif
You would include "Throw.h" before any headers that throw exceptions, perhaps using a compiler's force-include feature. You could compile the non-header-only Boost libraries with this, too. You could overload operator << to do different things with different exceptions, such as reporting the error in some fashion, or using platform specific code to detect if a debugger is attached and break if so. This would also have the advantage that it would to some extent allow your C++ programmers to use exception semantics in their own code.
If you come across cases where you don't want to terminate, and you're very clever and lucky, you might be able to make operator << translate the exception into a return value for the function. This would be difficult because the same exception could be thrown by functions with different return value types. You could return a Throw & from operator << and add conversion operators to Throw to make it turn into whatever the function wants. However, it would be difficult to know what an appropriate return value would be.
I think this simple header could allow Boost to be used in an environment that frowns on exceptions without any changes to Boost. Of course, I haven't tried any of it. Nick