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I'm working on an RS485 project, In the CPP file there are const variables declared in the following manner: 

#include <RS485_protocol.h>
const byte STX = '\2'; 
const byte ETX = '\3';

What does the '\2' and '\3' mean?

MichaelT
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mjrleap
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1 Answers1

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The '\2' and '\3' are characters with octal code 2 and 3. Which is nothing more then 2 and 3 in octal and in decimal. The author could simply write const byte STX = 2; const byte ETX = 3;.

Characters with ASCII code 2 and 3 are control characters STX (start of text) and ETX (end of text). Control characters are invisible characters used to control the terminal or as mark characters in communication.

Juraj
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  • Perhaps the question is more about the '' than the 2 and 3. A list is here: https://en.cppreference.com/w/cpp/language/escape – Jot Nov 17 '18 at 15:43