Macos symbol not found in flat namespace (but works on linux)

[spanky411]

Everything works fine in linux. When I run on macos, everything was going fine too until I started using dynamodb and the shared_ptr for AttributeValues.

symbol not found in flat namespace '__ZN3Aws8DynamoDB5Model14AttributeValue4SetLERKNSt3__16vectorINS3_10shared_ptrIS2_EENS_9AllocatorIS6_EEEE'
If I nm -U libaws-cpp-sdk-dynamodb.a, I get this
0000000000003dec T __ZN3Aws8DynamoDB5Model14AttributeValue4SetLERKNSt3__16vectorINS3_10shared_ptrIS2_EENS3_9allocatorIS6_EEEE

Note the difference
__ZN3Aws8DynamoDB5Model14AttributeValue4SetLERKNSt3__16vectorINS3_10shared_ptrIS2_EENS_9AllocatorIS6_EEEE
__ZN3Aws8DynamoDB5Model14AttributeValue4SetLERKNSt3__16vectorINS3_10shared_ptrIS2_EENS3_9allocatorIS6_EEEE

This is probably a super simple compiler/cmake thing, but I've been tearing my hair out over it.

I'm basically doing the exact same thing on linux and it works. The examples for dynamodb are sort of thin... is there a way to use the attributevalue without the shared pointers?

[sbiscigl]

The examples for dynamodb are sort of thin.

have you checked out the doc examples repo? theres a load of dynamo examples there, is there a specific thing youre trying to do that is missing from there?

This is probably a super simple compiler/cmake thing, but I've been tearing my hair out over it.

my guess is that you have multiple installations of the SDK on your mac and your application code is mixing up lincludes/linking the wrong version. how are you installing the SDK? how are you referencing and building your application?

[spanky411]

Yes. I haven't tried running the examples as-is, but I followed it pretty close (again, works fine on linux)

For example: in https://github.com/awsdocs/aws-doc-sdk-examples/blob/main/cpp/example_code/dynamodb/query_items.cpp#L60
This appears to be the offending line:

    Aws::Map<Aws::String, Aws::DynamoDB::Model::AttributeValue> attributeValues;
    attributeValues.emplace(":valueToMatch", partitionValue); <<<<<<<<<<<<<<<< this one

    request.SetExpressionAttributeValues(attributeValues);

which, on macos, results in the linker error:
symbol not found in flat namespace '__ZN3Aws8DynamoDB5Model14AttributeValue4SetSERKNSt3__112basic_stringIcNS3_11char_traitsIcEENS_9AllocatorIcEEEE'
If I comment the emplace line, it compiles and runs (but now the query is useless). emplace() apparently uses SetS() internally.

This similarly happens on all the other SetX methods on AttributeValue for example:
https://github.com/awsdocs/aws-doc-sdk-examples/blob/main/cpp/example_code/dynamodb/put_item.cpp#L58
If I use this exact same line, I get the same linker error (only on macos). If I comment it out, it compiles and runs (just doesn't do what its supposed to)

    putItemRequest.AddItem(albumTitleKey, Aws::DynamoDB::Model::AttributeValue().SetS(
            albumTitleValue));

[SergeyRyabinin]

Hello,
It seems that you have different versions of std library used at SDK build time and application build time.
They are very similar as their mangled names suggest but still different.
AWS C++ SDK by default disables exceptions and rtti, this may change the resulting std lib.
There is also a cmake flag for the SDK to use custom memory management in std:: types (which are wrapped into Aws::), -DCUSTOM_MEMORY_MANAGEMENT=OFF, please make sure this flag is consistent.

For your specific case, I'd suggest checking the exact gcc/clang compiler calls made at SDK and app build times, you can use cmake to dump commands into a json file:
https://cmake.org/cmake/help/latest/variable/CMAKE_EXPORT_COMPILE_COMMANDS.html

Best regards,
Sergey

[spanky411]

It was using a different compiler path, but they all mapped back to clang. I explicitly set my compiler to match. I also made sure to set DCUSTOM_MEMORY_MANAGEMENT=OFF, which I think is the default. Incidentally, with it ON, it compiles and runs past that symbol issue, but I didn't have much luck implementing the memorymanager and, somewhere along that path, I found some documentation indicating the documentation was very out of date on that topic (its unclear if that is still a viable alternative to my situation).

Do you see anything blatantly obvious. They looks like they should be compatible...?

Here's how I'm compiling the sdk (via CMAKE_EXPORT_COMPILE_COMMANDS):
/usr/bin/c++ -DAWS_ENABLE_DISPATCH_QUEUE -DAWS_ENABLE_KQUEUE -DAWS_TEST_REGION=US_EAST_1 -DCJSON_HIDE_SYMBOLS -DDEBUG_BUILD -DENABLED_REQUEST_COMPRESSION -DENABLED_ZLIB_REQUEST_COMPRESSION -DENABLE_CURL_CLIENT -DENFORCE_TLS_V1_2 -DPLATFORM_APPLE @CMakeFiles/aws-crt-cpp.dir/includes_CXX.rsp -g -std=gnu++11 -arch arm64 -mmacosx-version-min=13.0 -fvisibility=hidden -fvisibility-inlines-hidden -o CMakeFiles/aws-crt-cpp.dir/source/Allocator.cpp.o ................ ------- the aws source file

and here's how I'm compiling my code (note, I'm using scikit-build-core, but that goes through a cmake step):
/usr/bin/c++ -DAWS_ENABLE_DISPATCH_QUEUE -DAWS_ENABLE_KQUEUE -DAWS_SDK_VERSION_MAJOR=1 -DAWS_SDK_VERSION_MINOR=11 -DAWS_SDK_VERSION_PATCH=575 -DJWT_DISABLE_PICOJSON -DUSE_AWS_SDK -Dlibmytestlibrary_EXPORTS -I/Users/spanky/GitRepos/aws-sdk-cpp/dist/include -isystem /Users/spanky/GitRepos/aws-sdk-cpp/dist/macos/include -isystem /opt/homebrew/Cellar/[email protected]/3.13.3/Frameworks/Python.framework/Versions/3.13/include/python3.13 -O3 -DNDEBUG -std=gnu++11 -arch arm64 -fPIC -o CMakeFiles/............ ------- my sources