What does the \x1a characters mean
\x1A is CTRL+Z control character. It is also EOF marker.
\x1a
is a SUB control character, used to mark end of a file (EOF).
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.
It is a hexadecimal escape sequence for the SUB character.