Re: error: template argument for template type parameter must be a type template< class Allocator = std::allocator< none > >

From: Robert Jones (robertgbjones_at_[hidden])
Date: 2024-07-05 15:24:45

On Fri, 5 Jul 2024 at 15:48, Phil Phil via Boost-users <
boost-users_at_[hidden]> wrote:

>
> I try to port a c++ project to a new environment with clang++-17, libcxx
> 17 and std=c++17 for x64 Linux. Also, I switched form boost 1.65 to 1.84.
> Now I start getting errors in boost itself:
>
> /workspace/usr/include/boost/statechart/fifo_worker.hpp:55:45: error:
> template argument for template type parameter must be a type
>    55 | template< class Allocator = std::allocator< none > >
>
> I'm not sure if this answers your issue, but from §12.3.4 (p197) of C++
Templates
<https://www.amazon.co.uk/Templates-Complete-Guide-David-Vandevoorde/dp/0321714121/ref=sr_1_1?crid=1SNPB9AQYKH7U&dib=eyJ2IjoiMSJ9.b0YMM1EtQwSigfaRYI6qiFrhXcDLFPGBOmBMQHDFPla2BvLWwCfWPBW0N6KeBwdupdfKDTYnGanIFme0azAt_QwDrPREL7tv3tPhs9z5ObvZ6kEpj9NRTPz1JOZYsrexKH0Fe_oOcoFIFNQtsiaJuT831tbIkY5n7SMEj-mNhhH-DlkR3EogCv4DjhARxByEAXE0OowZbvC2WiKPbvnnZ7PtWKzuRX7c3CampkYGHlo.SMnSkcLgYS4TkN1uSxVXGy2ACu9xaT-LcNLkg6fK5yo&dib_tag=se&keywords=templates+c%2B%2B&qid=1720192741&sprefix=templates+c%2B%2B%2Caps%2C89&sr=8-1>
,

Prior to C++17, default template template arguments of a template template
argument were ignored (but if the template template parameter has default
arguments, they are considered during the instantiation of the template).

HTHs, Rob