php man page for preg_quote

PREG_QUOTE(3)								 1							     PREG_QUOTE(3)

preg_quote - Quote regular expression characters

SYNOPSIS
       string preg_quote NULL (string  $str, [string  $delimiter])

DESCRIPTION
       preg_quote(3)  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: .  + * ? [ ^ ] $ ( ) { } = ! < > | : -

PARAMETERS
	      o $str
		- The input string.

	      o $delimiter
		- If the optional $delimiter is specified, it will also be escaped. This is useful for escaping the delimiter that is required	by
		the PCRE functions. The / is the most commonly used delimiter.

RETURN VALUES
	Returns the quoted (escaped) string.

CHANGELOG
       +--------+--------------------------------+
       |Version |				 |
       |	|				 |
       |	|	   Description		 |
       |	|				 |
       +--------+--------------------------------+
       | 5.3.0	|				 |
       |	|				 |
       |	|  The - character is now quoted |
       |	|				 |
       +--------+--------------------------------+
EXAMPLES
       Example #1

	      preg_quote(3) example

	      <?php
	      $keywords = '$40 for a g3/400';
	      $keywords = preg_quote($keywords, '/');
	      echo $keywords; // returns $40 for a g3/400
	      ?>

       Example #2

	      Italicizing a word within some text

	      <?php
	      // In this example, preg_quote($word) is used to keep the
	      // asterisks from having special meaning to the regular
	      // expression.

	      $textbody = "This book is *very* difficult to find.";
	      $word = "*very*";
	      $textbody = preg_replace ("/" . preg_quote($word, '/') . "/",
					"<i>" . $word . "</i>",
					$textbody);
	      ?>

NOTES
       Note

	      This function is binary-safe.

SEE ALSO
       PCRE Patterns, escapeshellcmd(3).

PHP Documentation Group 													     PREG_QUOTE(3)