On Thu, August 26, 2010 12:49 am, Lorenzo Caminiti wrote:
I am trying to use Boost.ScopeExit parameter binding mechanism to implement Boost.LocalFunction. To do so, I need to use some internal ScopeExit code to detect the type of `this` and bind its value to the local function declaration.
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2) Do you know of a workaround for this problem?
I posted a workaround for this a while back (http://lists.boost.org/Archives/boost/2009/03/149540.php) which used type indexing (where the index for typeof(this) is captured outside of a template parameter list) to avoid specifying 'this' in a template parameter list. The mechanics for the solution came from boost.typeof.
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I have attached my latest version of the patch which still applies fine to 1.44 and, I think, works on cl versions from vc7.1 upwards.
You should be able to use the same type index trick in localfunction. The key definition is the function-style macro BOOST_SCOPE_EXIT_TYPEDEF_TYPEOF_THIS().
Why is this patch defining the following accessors for the ScopeExit local struct? +#define BOOST_SCOPE_EXIT_DEFINE_THIS_ACCESSOR_this(id) \ + inline BOOST_PP_CAT(se_this_type,id) operator->() { return boost_se_params_->se_this; } \ + inline BOOST_PP_CAT(se_this_type,id) operator*() { return boost_se_params_->se_this; } \ + inline operator BOOST_PP_CAT(se_this_type,id)() { return boost_se_params_->se_this; } \ I think these are meant to use `this` to access the bound object instead of the local struct object. However, these accessors don't work because `this->` (and `*this`) never calls the overloaded `operator->`: #include <iostream> struct obj_t { int x; int f() { return -1; } } obj; typedef obj_t* this_t; int main() { struct l { void operator()() { std::cout << this->x << std::endl; // error :(( std::cout << this->f() << std::endl; // error :(( std::cout << this->operator->()->x << std::endl; // ok std::cout << this->operator->()->f() << std::endl; // ok } this_t operator->() { return &obj; } this_t operator*() { return &obj; } operator this_t() { return &obj; } int f; } ll; ll(); return 0; } Am I not understanding the purpose of the patch's assessors correctly? Thanks for the clarification. -- Lorenzo -- View this message in context: http://boost.2283326.n4.nabble.com/scope-exit-MSVC-error-C2355-this-can-only... Sent from the Boost - Dev mailing list archive at Nabble.com.