错误 C2660: 'std::allocator<char> ::allocate': function 不占用 2 arguments</char>

Question

Code:

#include <string>

#include <boost/format.hpp>

int main() {
    boost::format fmt;
    auto str = fmt % L"";
}

Errors:

1>D:.conan\a9fe50\1\include\boost\format\alt_sstream_impl.hpp(261,1): error C2660: 'std::allocator::allocate': function does not take 2 arguments 1>C:\Program Files (x86)\Microsoft Visual Studio\2019\Community\VC\Tools\MSVC\14.29.30037\include\xmemory(838,65): message: see declaration of 'std::allocator::allocate' 1>D:.conan\a9fe50\1\include\boost\format\alt_sstream_impl.hpp(228): message: while compiling class template member function 'int boost::io::basic_altstringbuf<Ch,Tr,Alloc>::overflow(int)' 1>
with 1> [ 1> Ch=char, 1>
Tr=std::char_traits, 1> Alloc=std::allocator 1> ] 1>D:.conan\a9fe50\1\include\boost\format\format_class.hpp(173): message: see reference to class template instantiation 'boost::io::basic_altstringbuf<Ch,Tr,Alloc>' being compiled 1>
with 1> [ 1> Ch=char, 1>
Tr=std::char_traits, 1> Alloc=std::allocator 1> ] 1>D:\Documents\source\repos\ConsoleApplication3\ConsoleApplication3\ConsoleApplication3.cpp(6): message: see reference to class template instantiation 'boost::basic_format<char,std::char_traits,std::allocator>' being compiled 1>Generating Code... 1>Done building project "ConsoleApplication3.vcxproj" -- FAILED.

Environment

• OS: Win10-64bit
• VC++ 2019 16.10.0
• Configuration: x86
• SDK version: 10.0(latest installed version)
• Language: std:c++latest
• Boost: 1.73

I upgraded VC++ today from 16.9 to 16.10, then compilation was broken. It only happens when I use std:c++latest , but works fine with 'std:c++17'.

Answer 1

The library lacks c++20 support (see https://en.cppreference.com/w/cpp/memory/allocator/allocate )

You can, for now, opt for c++17 compilation. Also, see whether they know about this issue, and if not report it to the developers.

Side Notes

• I take it the sample is reduced, but it seems to me the literal ought to be narrow, or the fmt ought to be wformat
• It appears that Boost 1.76 doesn't have this problem so, try upgrading boost

Answer 2

I realize this is a few months old now, but I just hit this same issue with boost 1.70 after upgrading VS 2019. All I did was remove the 2nd argument to the 'allocate' call on line 261 of alt_sstream_impl.hpp, since it's just a hint/optimization that was deprecated in c++ 17, and now gone in c++ 20. Fortunately, it's an inline method, so no linker issues.

Answer 3

You can define _HAS_DEPRECATED_ALLOCATOR_MEMBERS

It will reenable the removed "allocator stuff" in C++20 even when you compile with C++20 standard selected.