Undefined reference to vformat

[k0zmo]

Following program fails in linker stage with an undefined reference to vformat. It happens with GCC 7.3 (MSYS2) and MSVC 14.1 but only in release-flavour configurations (all three of them). I suspect the inline keyword on vformat() definition in format.h can be a culprit here (in debug configuration compiler does not optimize aggressively inline functions).

It doesn't exhibit any problems if I change include fmt/format.h instead of fmt/core.h.

cmake_minimum_required(VERSION 3.0)
project(fmt-test)

add_subdirectory(fmt)

add_executable(fmt-test main.cpp)
target_link_libraries(fmt-test PRIVATE fmt::fmt)

#include <fmt/core.h>

int main(int argc, char* argv[])
{
    fmt::format("{}", argc);
}

[vitaut]

Could you post the output of nm libfmt.a (or dumpbin fmt.lib)?

[vitaut]

323b92b is a tentative fix, although I wasn't able to repro the issue on my version of gcc. Please let me know if it works for you and I'll merge into master.

[k0zmo]

This fixes it in both GCC and MSVC.

Here's the output from nm | c++filt | grep vformat:
nm.after.log
nm.before.log

and objdump /SYMBOLS | grep vformat:
dumpbin.after.log
dumpbin.before.log

[vitaut]

Merged the fix into master, thanks for reporting and confirming that it works!