php -\x1a 字符是什么意思

Question

\x1a 字符是什么意思，mysql_real_escape_string 为什么要转义它？

来自文档:

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.

ASCII 字符引用将其描述为 替换字符，但这并没有说明太多。

Answer 1

这是一个 Unicode escape sequence, in hexadecimal (base 16) . \x1a 是 "substitute" character .

另请参阅:https://en.wikipedia.org/wiki/Substitute_character

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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.