c++ - Is typename required or not here? -


consider code:

#include <memory>  template <class t, class deleter = std::default_delete<t>> class unique_ptr_wrapper: public std::unique_ptr<t, deleter> { public:     using typename std::unique_ptr<t, deleter>::unique_ptr;     operator t* () const {return this->get();} };  int main() {     unique_ptr_wrapper<int> upw{new int{42}}; }

g++5.1 compiles fine, although clang++ complains

error: typename allowed identifiers only

i agree don't have identifier here, typename not required. forbidden? compiler required @ least emit diagnostic?

edit code compiled fine without typename both g++ , clang++.

update seems g++ bug, reported here.

[class.inhctor]/p1, emphasis mine:

a using-declaration (7.3.3) names constructor implicitly declares set of inheriting constructors.

a constructor not type.

[temp.res]/p3-4:

3 when qualified-id intended refer type not member of current instantiation (14.6.2.1) , nested-name-specifier refers dependent type, shall prefixed keyword typename, forming typename-specifier. if qualified-id in typename-specifier not denote type, program ill-formed.

4 if specialization of template instantiated set of template-arguments such qualified-id prefixed typename not denote type, specialization ill-formed. usual qualified name lookup (3.4.3) used find qualified-id in presence of typename.

[class.qual]/p2:

in lookup in function names not ignored , nested-name-specifier nominates class c:

  • if name specified after nested-name-specifier, when looked in c, injected-class-name of c (clause 9), or

  • in using-declaration (7.3.3) member-declaration, if name specified after nested-name-specifier same identifier or simple-template-id’s template-name in last component of nested-name-specifier,

the name instead considered name constructor of class c.

applying "usual qualified name lookup" rules found in [class.qual], std::unique_ptr<t, deleter>::unique_ptr names constructor. not denote type. therefore, above quote [temp.res], program ill-formed (with diagnostic required).

in other words, appears gcc bug (though clang's error message use improvement too).


Comments

Post a Comment

Popular posts from this blog

angularjs - ADAL JS Angular- WebAPI add a new role claim to the token -

i have created angular spa webapi backend using adal js authentication.as there no roles in ad, need manually add role claims in order give users access different api controllers. the roles stored in database. expecting inject claim through call webapi after authentication ad. webapi code might this. identity.addclaim(new claim("role", "user")); var ticket = new authenticationticket(identity, props); var accesstoken = startup.oauthbeareroptions.accesstokenformat.protect(ticket); is possible replace adal idtoken new token? is viable solution or there other better way handle this? as initial token generated azuread, possible edit token add new claim? appreciated. graph api supporting group claims. see here: http://justazure.com/azure-active-directory-part-4-group-claims/ if @ examples on page, users assigned groups , app can check group in claims. in current version of portal, need app manifest , modify it.
Read more

node.js - Using Node without global install -

i'm working on few node & electron (atom shell) projects , i'm curious how them work without user having install node globally. i've seen few applications including node directory in project contains node.exe binary. how go setting node project use binary? edit: thought should add, i've searched everywhere answer this, unrelated results.
Read more

php - CakePHP HttpSockets send array of paramms -

i problem when make request (i can request). $link = 'http://uri/path/?param1=1&sid=2&sid=3&sid=4' $http = $httpsocket = new httpsocket(); $res = $httpsocket->get($link); if check request pr($http); i see : [line] => /url/path/?param1=1&sid%5b0%5d=2&sid%5b1%5d=3&sid%5b2%5d=4 http/1.1 and i'm getting empty response because server doesn't know parameters sid%5b0%5d=2 when try send parameters array : $data = array('param1' => '1', 'sid' => array('2','3', '4')); i see same changes %5b0%5d - additional indexes. how fix it? unfortunately , can not change server side, if send request in browser, i'll normal response in json format. when make request, can parameters this: $param1 = $_get['param1']; $sid= $_get['sid']; tip: use diferente names parameters. have multiples sid. use sid1, sid2, sid3... update: can parameters this:...
Read more