0235			[U] Unknown escape sequence.
	Explicitly undefined				REFERENCE - ISO:C90-6.1.3.4 Description, ISO:C90-6.9.2 Future Language Directions

• a simple-escape-sequence, i.e. \',  \",  \?,  \\,  \a,  \b,  \f,  \n,  \r,  \t,  \v
• an octal-escape-sequence, i.e. \   followed by up to three octal digits
• a hexadecimal-escape-sequence, i.e. \x   followed by any number of hexadecimal digits

/*PRQA S 1305,2017,3211,3408,3602,3625,3610,3628 ++*/

const char essq = '\'';
const char esbs = '\\';
const char esf = '\f';
const char esn = '\n';
const char est = '\t';
const char eon = '\012';
const char ehn = '\x0D';
const char esc = '\c';               /* Message 0235 */
const char esz = '\z';               /* Message 0235 */