Richard –

This usually happens because you're compiling with one standard library (e.g. libc++, the default on clang) while your boost libraries were compiled with another (e.g. libstdc++, the default on gcc).

That makes sense. Does my MacOS program need to be compiled for GCC (IE GNU C++17 / GNU C++20), and then linked with libstdc++ to be compatible with the default build of Boost, or the opposite: build Boost and link with libc++? I saw that there’s a list of toolsets, but in the “getting started with unix variants”, included with the 1_85_0 .zip package, there is no listing for toolset=clang or toolset=clang-darwin. Nor is there any mention of clang on: https://www.boost.org/doc/libs/1_85_0/more/getting_started/unix-variants.htm... Stephen -- ------------------------------ Message: 5 Date: Thu, 11 Jul 2024 09:43:01 +0200 From: Richard Hodges To: boost@lists.boost.org Subject: Re: [boost] Updating from 1_71_0 to 1_85_0: "No member named 'memcpy' in namespace 'std::__1'" Message-ID: Content-Type: text/plain; charset="UTF-8" This usually happens because you're compiling with one standard library (e.g. libc++, the default on clang) while your boost libraries were compiled with another (e.g. libstdc++, the default on gcc). R On Thu, 11 Jul 2024 at 02:21, Stephen Greenfield via Boost < boost@lists.boost.org> wrote:

Dear Boost gurus,

Building on MacOS 12.7.3, Xcode 13.4.1, C++ dialect = C++17. Deployment target is 10.15. This particular project is x86_64 architecture. I?m only linking libboost_filesystem.a and libboost_iostreams.a (I show my build boost build steps at the end).

When updating from Boost 1_71_0 to 1_85_0, I?m suddenly encountering these kinds of errors:

/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX12.3.sdk/usr/include/c++/v1/__functional/hash.h:40:5: No member named 'memcpy' in namespace 'std::__1'; did you mean simply 'memcpy'?

/Users/stephen/dev/Boost Libraries/boost_1_85_0/boost/system/detail/append_int.hpp:23:5: No member named 'snprintf' in namespace 'boost::system::detail'; did you mean simply 'snprintf'?

In file included from /Users/stephen/dev/Screenwriter/ScreenWriterX/ScreenWriterX/Screenwriter Sources/Text Engine/CThingEdit.cp:22:

In file included from ../ScreenWriterX/ScreenWriterX/Screenwriter Sources/Text Engine/CThingEdit.h:61:

In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX12.3.sdk/usr/include/c++/v1/string:522:

In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX12.3.sdk/usr/include/c++/v1/algorithm:653:

In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX12.3.sdk/usr/include/c++/v1/functional:500:

In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX12.3.sdk/usr/include/c++/v1/__functional/function.h:20:

In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX12.3.sdk/usr/include/c++/v1/__memory/shared_ptr.h:25:

In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX12.3.sdk/usr/include/c++/v1/__memory/unique_ptr.h:15:

/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX12.3.sdk/usr/include/c++/v1/__functional/hash.h:40:5: error: no member named 'memcpy' in namespace 'std::__1'; did you mean simply 'memcpy'?

_VSTD::memcpy(&__r, __p, sizeof(__r));

^~~~~~~

In file included from <built-in>:1:

In file included from /Users/stephen/dev/Screenwriter/ScreenWriterX/ScreenWriterX/Screenwriter Sources/Screenwriter_Prefix.pch:505:

In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX12.3.sdk/usr/include/MacTypes.h:44:

In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX12.3.sdk/usr/include/c++/v1/stdbool.h:22:

/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX12.3.sdk/usr/include/c++/v1/__config:858:15: note: expanded from macro '_VSTD'

#define _VSTD std::_LIBCPP_ABI_NAMESPACE

^

In file included from /Users/stephen/dev/Screenwriter/ScreenWriterX/ScreenWriterX/Screenwriter Sources/Text Engine/CThingEdit.cp:22:

In file included from ../ScreenWriterX/ScreenWriterX/Screenwriter Sources/Text Engine/CThingEdit.h:61:

In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX12.3.sdk/usr/include/c++/v1/string:522:

In file included from /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX12.3.sdk/usr/include/c++/v1/algorithm:652:

/Users/stephen/dev/Boost Libraries/boost_1_85_0/boost/compatibility/cpp_c_headers/cstring:22:11: note: 'memcpy' declared here

using ::memcpy;

^ ?this is for all sorts of symbols. ALSO:

Showing All Errors Only

/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX12.3.sdk/usr/include/c++/v1/filesystem:2635:5: Use of undeclared identifier '_LIBCPP_UNREACHABLE'

When including:

#include <fstream>

The libraries were build using:

./bootstrap.sh cxxflags="-arch x86_64 -arch arm64" cflags="-arch x86_64 -arch arm64" linkflags="-arch x86_64 -arch arm64"

./b2 toolset=clang-darwin target-os=darwin architecture=arm abi=aapcs cxxflags="-arch arm64" cflags="-arch arm64" linkflags="-arch arm64" -a

mkdir -p arm64 && cp stage/lib/*.* arm64

./b2 toolset=clang-darwin target-os=darwin architecture=x86 cxxflags="-arch x86_64" cflags="-arch x86_64" linkflags="-arch x86_64" abi=sysv binary-format=mach-o -a

mkdir x86_64 && cp stage/lib/*.* x86_64

The intention was for me to eventually make UNIVERSAL dylibs using lipo ? but for now, I just want to get my build back to functioning with Boost 1_85_0.

NOTE that I?m continuing to use Boost?s Filesystem ? even though I THINK Xcode?s C++20 might now support std::filesystem.

I?ve searched all over for the answer ? even consulted ChatGPT ? but haven?t found a solution. But this seems like something bone-headed I?ve missed.

Stephen

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