provide logging macro signature that accepts std::string

[wjwwood]

Feature request

Feature description

I'd like to have std::string (and possibly other common string containter) friendly logging macros.

For example, right now you must make logging calls like this:

std::string msg = "some error message from elsewhere";
RCLCPP_INFO(logger, ("some suffix: " + msg).c_str());

But I'd like to write:

std::string msg = "some error message from elsewhere";
RCLCPP_INFO(logger, "some suffix: " + msg);
// or just...
RCLCPP_INFO(logger, msg);

Implementation considerations

I think a helper function could make the macros simple, something like:

#include <string>

using namespace std::string_literals;

const char *
get_c_string(const char * string_in)
{
  return string_in;
}

const char *
get_c_string(const std::string & string_in)
{
  return string_in.c_str();
}

#define LOG_INFO(msg) printf("%s\n", get_c_string(msg));

int main()
{
  LOG_INFO("plain c string");
  std::string a_str("a local std::string");
  LOG_INFO(a_str);
  LOG_INFO(std::string("a temporary std::string"));
  LOG_INFO("a std::string literal"s);
}

[fmrico]

Hi all,

I think I have a possible solution, in 9a99a84

Best
Francisco

[wjwwood]

Thanks @fmrico, is that part of a pull request? If not could open one to that effect?

[wjwwood]

Disregard my previous comment, I found the pull request (#573) :D