Variable length string logging

[hkpackage]

How to log a variable length string?
For example in printf I do this:

#define BUFFER_SIZE 10
char buffer[BUFFER_SIZE];

buffer = "hello";
int len_to_print = strlen(buffer);   // just a demostration, string not necessary null terminated
printf("%.*s", len_to_print, buffer);

[odygrd]

hey,

It is not directly supported. However, you can use std::string_view for that.

Even when you use std::string_view, a deep copy of the string is taken on the hot path and pushed into a queue to get logged later, so even if your original buffer goes out of scope at any point, the correct string will still be printed.

#include "quill/Quill.h"
#include <string_view>
#include <string>

constexpr std::string_view var_str(char const* str, size_t len)
{
  return std::string_view {str, len};
}

int main()
{
  quill::start();

  char buffer[10];
  size_t constexpr str_len = 5;
  std::memcpy(&buffer[0], "hello", str_len);

  LOG_INFO(quill::get_logger(), "variable string {}", var_str(&buffer[0], str_len));
  LOG_INFO(quill::get_logger(), "variable string {}", std::string_view{&buffer[0], str_len});
}