spdlog::debug( as well as info etc ...) breaks at link time when no argument in fmt

[grbba]

Hello i just started using spdlog and run into a strange issue.
In my code I call

spdlog::debug("Adding connections between the vertices of the crossing"); which gives me a linker error

Undefined symbols for architecture x86_64:
[build]   "spdlog::details::log_msg::log_msg(spdlog::source_loc, fmt::v7::basic_string_view<char>, spdlog::level::level_enum, fmt::v7::basic_string_view<char>)", referenced from:
[build]       void spdlog::logger::log_<fmt::v7::basic_string_view<char>, short, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, int, int, unsigned long>(spdlog::source_loc, spdlog::level::level_enum, fmt::v7::basic_string_view<char> const&, short&&, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >&&, int&&, int&&, unsigned long&&) in DccVertex.cpp.o
[build]       void spdlog::logger::log_<fmt::v7::basic_string_view<char>, short, short, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, int, int, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, int, int>(spdlog::source_loc, spdlog::level::level_enum, fmt::v7::basic_string_view<char> const&, short&&, short&&, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >&&, int&&, int&&, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >&&, int&&, int&&) in DccVertex.cpp.o
[build]       void spdlog::logger::log_<fmt::v7::basic_string_view<char>, int&, int&>(spdlog::source_loc, spdlog::level::level_enum, fmt::v7::basic_string_view<char> const&, int&, int&) in DccVertex.cpp.o
[build]       void spdlog::logger::log_<fmt::v7::basic_string_view<char>, short&, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, int&, int&, unsigned long>(spdlog::source_loc, spdlog::level::level_enum, fmt::v7::basic_string_view<char> const&, short&, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >&&, int&, int&, unsigned long&&) in DccVertex.cpp.o
[build]       DccGraph::buildCrossingVertex(int, int, DccModel::Trackelement*) in DccGraph.cpp.o
[build]       DccGraph::build(DccModel::DccExLayout*) in DccGraph.cpp.o
[build]       DccGraph::printGraph() in DccGraph.cpp.o
[build]       ...

but if i call it with an argument as follows:

spdlog::debug("Adding connections between the vertices of the {}","crossing");

it all works and no linker error. I am a bit at a loss here what the reason for this could be.
I use CPM.cmake as dependency manager and load the fmt library using CPM.cmake after loading spdlog the same way in my CMakeLists if that is of any importance.

Any hint would be welcome Thanks a lot.

[tt4g]

void spdlog::logger::log_<fmt::v7::basic_string_view<char>, short&, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, int&, int&, unsigned long>(spdlog::source_loc, spdlog::level::level_enum, fmt::v7::basic_string_view<char> const&, short&, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >&&, int&, int&, unsigned long&&) in DccVertex.cpp.o

When spdlog::debug("Adding connections between the vertices of the crossing") is called, spdlog::logger::debug() function will call spdlog::logger::log(level::level_enum, const FormatString &, Args&&).

spdlog/include/spdlog/logger.h

Lines 91 to 94 in 0613dbc

	void log(level::level_enum lvl, const FormatString &fmt, Args&&...args)
	{
	log(source_loc{}, lvl, fmt, std::forward<Args>(args)...);
	}

However, in the link error message, short&, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >&&, int&, int& and unsigned long&& appear as arguments after fmt::v7::basic_string_view<char>.
The arguments do not match the submitted code.
You are missing something.

[grbba]

yes i was sure that i am missing something. The trick in the end was as i am using fmt also as a package to

a) to put fmt first to be loaded by CPM.cmake as dependency before spdlog and
b) set the SPDLOG_FMT_EXTERNAL flag.

No more linker errors. I guess there must have been some conflict concerning the fmt lib Thanks for your reply in any case
Have a good day.