string preg_quote(string str);preg_quote() takes str and puts a backslash in front of every character that is part of the regular expression syntax. This is useful if you have a run-time string that you need to match in some text and the string may contain special regex characters.
The special regular expression characters are:
. \\ + * ? [ ^ ] $ ( ) { } = ! < > | :
Note: This function was added in PHP 3.0.9.