undefined reference to `vtable for spdlog::async_logger' when compiling about spdlog HOT 5 OPEN

The link will fail if you are not using the same version of spdlog and fmt as the vendor.

EDIT: Compilation options must also match.

from spdlog.

You also need to define the SPDLOG_FMT_EXTERNAL macro to make spdlog use external fmt: -DSPDLOG_COMPILED_LIB -DSPDLOG_FMT_EXTERNAL

from spdlog.

Oh, I had overlooked that.
You must build all the src/*.cpp files, since building only src/spdlog.cpp will result in missing symbols.

from spdlog.

Oh, I had overlooked that. You must build all the src/*.cpp files, since building only src/spdlog.cpp will result in missing symbols.

But in installation file it says as one of the option to use spdlog:
Or copy src/spdlog.cpp to your build tree and pass the -DSPDLOG_COMPILED_LIB to the compiler

& with current version of the vendor APIs it is working.

We use the vendor APIs in our code & now we have to migrate our code to compile with vendor's new version of APIs (which use fmt, the current version of APIs do no use fmt). The vendor has provided us with fmt header files and informed us they use only fmt-8.1.1.

We tried DSPDLOG_FMT_EXTERNAL and it did not help.

from spdlog.

But in installation file it says as one of the option to use spdlog:
Or copy src/spdlog.cpp to your build tree and pass the -DSPDLOG_COMPILED_LIB to the compiler

Where does it say that?
As far as I know, there is no such documentation in the spdlog repository.
If the vendor is customizing the spdlog, then your question here cannot be resolved.

from spdlog.