[SOLVED] How to use library fmt with clang

Issue

My code is like

#include "fmt/compile.h"

int main() {
  using namespace fmt::literals;
  auto result = fmt::format("{}"_cf, FMT_VERSION);
  printf("%s", result.data());
}

It cannot compile with clang. The compilation result can be seen here

How can I make it work with clang. thx

Solution

Build of fmt depends on a bunch of macros. Here, build fails because operator () ""_cf is not defined in the clang version. If you look at the code you'll see it depends on macro FMT_USE_NONTYPE_TEMPLATE_ARGS for whatever reason.

Probably godbolt at inclusion of fmt doesn't declare the macro to be true for clang.

Regardless, if you simply add the line #define FMT_USE_NONTYPE_TEMPLATE_ARGS true before including fmt the code will compile on clang too. This is not recommended solution, the macro should be defined at build level, not directly in the code.

Answered By - ALX23z

Answer Checked By - Mary Flores (WPSolving Volunteer)