AMDG On 2/6/2011 8:09 PM, Jeffrey Lee Hellrung, Jr. wrote:
On 2/6/2011 5:46 PM, Lorenzo Caminiti wrote:
On Sun, Feb 6, 2011 at 3:23 PM, Jeffrey Lee Hellrung, Jr. <jhellrung@ucla.edu> wrote:
On 2/6/2011 9:17 AM, Lorenzo Caminiti wrote: [...]
boost::scope_exit::aux::declared< boost::scope_exit::aux::resolve< sizeof(boost_local_auxXargs)>::cmp1<0>::cmp2> boost_local_auxXargs;
Shouldn't the name boost_local_auxXargs have some kind of line number or counter or function name pasted into it to prevent name collision of multiple BOOST_LOCAL_FUNCTION declarations in the same scope?
No, this has to be a global extern variable declared as:
extern boost::scope_exit::aux::undeclared boost_local_auxXargs;
in one of Boost.Local headers. It's a trick carried over 100% from Boost.ScopeExit (as I understand it, this is because only global or static variables can be used from within a nested block http://lists.boost.org/Archives/boost/2006/11/113658.php).
Ugh, okay ;) Will read the link.
That link isn't very relevant. This code is one of the most awful hacks around. Basically, it takes advantage of the template argument list/ comparison operator ambiguity to declare a variable iff it hasn't already been declared in that scope. The second occurrence is parsed as (boost::scope_exit::aux::declared< (boost::scope_exit::aux::resolve< sizeof(boost_local_auxXargs)>::cmp1 < 0)>::cmp2 > boost_local_auxXargs); which is a no-op. In Christ, Steven Watanabe