[C++] Check if CHAR fields are printable

[trozen]

Sometimes I'm getting messages with CHAR fields, that are set to 0 for example. This breaks logging, as binary data is mixed with text.

Would it be possible to change the way CHAR fields are printed currently:

            builder << '"' << (char)writer.tradeCondition() << '"';

to something like:

            if (std::isprint(writer.tradeCondition())) {
                builder << '"' << (char)writer.tradeCondition() << '"';
            } else {
                builder << (int)writer.tradeCondition();
            }

[tmontgomery]

Feel free to send a PR for this.

[rigtorp]

Remember this will cause the output to be locale dependent.