What does the \x1a characters mean
ascii, mysql, php
Solution
It's a Unicode escape sequence, in hexadecimal (base 16). `\x1a` is the "substitute" character.
See also: https://en.wikipedia.org/wiki/Substitute_character
Why does `mysql_real_escape_string` escape it?
According to the documentation,
Strictly speaking, MySQL requires only that backslash and the quote character used to quote the string in the query be escaped. `mysql_real_escape_string()` quotes the other characters to make them easier to read in log files.
Problem
What does the `\x1a` character mean and why does `mysql_real_escape_string` escape it? From the documentation: mysql_real_escape_string() calls MySQL's library function mysql_real_escape_string, which prepends backslashes to the following characters: \x00, \n, \r, \, ', " and \x1a. A ASCII Characters reference describes it as `Substitute character`, but this doesn't say much.