C++ source

#include 
#include 
#include 


void log(const std::string_view message,
         const std::source_location location = 
               std::source_location::current())
{
    std::cout << "file: "
              << location.file_name() << "("
              << location.line() << ":"
              << location.column() << ") `"
              << location.function_name() << "`: "
              << message << 'n';
}
 
template  void fun(T x)
{
    log(x);
}
 
int main(int, char*[])
{
    log("Hello world!");
    fun("Hello C++20!");
}