Static linking is not working, C++20, libpq REL_16_2,

[adastreamer]

Hello, here is what I'm getting linking the static library.

System: Debian
Docker image gcc:13.2 (pre-installed libpq is uninstalled to process build from scratch)

/app/vendor/libpqxx/include/pqxx/strconv.hxx:80: undefined reference to `pqxx::internal::demangle_type_name[abi:cxx11](char const*)'
/usr/bin/ld: /app/vendor/libpqxx/include/pqxx/strconv.hxx:80: undefined reference to `pqxx::internal::demangle_type_name[abi:cxx11](char const*)'
/usr/bin/ld: /app/vendor/libpqxx/include/pqxx/strconv.hxx:80: undefined reference to `pqxx::internal::demangle_type_name[abi:cxx11](char const*)'
/usr/bin/ld: /app/vendor/libpqxx/include/pqxx/strconv.hxx:80: undefined reference to `pqxx::internal::demangle_type_name[abi:cxx11](char const*)'
/usr/bin/ld: /app/vendor/libpqxx/include/pqxx/strconv.hxx:80: undefined reference to `pqxx::internal::demangle_type_name[abi:cxx11](char const*)'
/usr/bin/ld: CMakeFiles/server.dir/src/cmd/server.cpp.o:/app/vendor/libpqxx/include/pqxx/strconv.hxx:80: more undefined references to `pqxx::internal::demangle_type_name[abi:cxx11](char const*)' follow
/usr/bin/ld: CMakeFiles/server.dir/src/cmd/server.cpp.o: in function `pqxx::field::view() const &':
/app/vendor/libpqxx/include/pqxx/field.hxx:113: undefined reference to `pqxx::field::c_str() const &'
/usr/bin/ld: /app/vendor/libpqxx/include/pqxx/field.hxx:113: undefined reference to `pqxx::field::size() const'
...
(and much more errors)

Build command I use: ./configure --disable-documentation CXXFLAGS="-std=c++20 -fPIC -O3 -I/app/vendor/postgres/src/interfaces/libpq" --with-postgres-lib=/app/vendor/postgres/src/interfaces/libpq --with-postgres-include=/app/vendor/postgres/src/include --disable-shared --enable-static && make

Then trying to link using CMake with my program:

...
add_library(pqxx OBJECT IMPORTED)
set_target_properties(pqxx PROPERTIES IMPORTED_LOCATION /app/vendor/libpqxx/src/.libs/libpqxx.a)

add_library(pq OBJECT IMPORTED)
set_target_properties(pq PROPERTIES IMPORTED_LOCATION /app/vendor/postgres/src/interfaces/libpq/libpq.a)
...

add_executable(...

target_link_libraries(server pq)
target_link_libraries(server pqxx)

Building and linking via CMake's add_subdirectory produces the same result.

Tried to rebuild using different flags and not using fPIC - the same result.

Does anyone have ideas what is this problem about?

[tt4g]

A very similar issue was reported, but the cause could not be determined: #820

Does the same problem occur when compiling with other versions of GCC or with Clang?

[jtv]

@adastreamer you're using libpqxx straight from its build directory, without installing it... Did you add the include/ directory from the libpqxx build tree to your app's include path?

Without that, the app build won't be able to find libpqxx's configuration header.

[adastreamer]

A very similar issue was reported, but the cause could not be determined: #820

Does the same problem occur when compiling with other versions of GCC or with Clang?

Yes, tried different versions and standards

[adastreamer]

@adastreamer you're using libpqxx straight from its build directory, without installing it... Did you add the include/ directory from the libpqxx build tree to your app's include path?

Without that, the app build won't be able to find libpqxx's configuration header.

I do a static build, could you please list the .a/.so libs which describe the missing symbols? And yes, of course, cmake includes directories automatically, but I also tried to pick manually the following directories:

     PUBLIC vendor/libpqxx/include
     PUBLIC vendor/libpqxx/build/include
     PUBLIC vendor/libpqxx/build/include/pqxx

[adastreamer]

@adastreamer you're using libpqxx straight from its build directory, without installing it... Did you add the include/ directory from the libpqxx build tree to your app's include path?
Without that, the app build won't be able to find libpqxx's configuration header.

I do a static build, could you please list the .a/.so libs which describe the missing symbols? And yes, of course, cmake includes directories automatically, but I also tried to pick manually the following directories:

     PUBLIC vendor/libpqxx/include
     PUBLIC vendor/libpqxx/build/include
     PUBLIC vendor/libpqxx/build/include/pqxx

Anyway, I will double check one more time and provide results if I do not missing anything

[jtv]

Note these two details though:

1. Do not add include/pqxx to your include path. The pqxx part should always be explicit in the #include directive.
2. Put the build directory's include before the source directory's.

[adastreamer]

Note these two details though:

1. Do not add include/pqxx to your include path. The pqxx part should always be explicit in the #include directive.
2. Put the build directory's include before the source directory's.

I will check and let you know.

[jtv]

Thanks.

[adastreamer]

Thanks.

The issue was related to cmake configuration, especially in regards to the linking stage. Seems like it's not been automatically set in the right order if app consists of multiple libraries. I wrote a simple Makefile and recompiled everything step by step, linked manually, everything seems working.

Sorry for disturbing you.

[jtv]

Glad it's resolved @adastreamer .

[jtv]

In #828 we found that the real problem was a bad command line: in that case the compilation was done with g++ -lpqxx -lpq app.cxx. Changing it to g++ app.cxx -lpqxx -lpq solved the problem.