>- >CLASS="emphasis"
>>i> (PCRE_CASELESS)
>- >
>
> If this modifier is set, letters in the pattern match both
> upper and lower case letters.
>
> >- >CLASS="emphasis"
>>m> (PCRE_MULTILINE)
>- >
>
> By default, PCRE treats the subject string as consisting of a
> single "line" of characters (even if it actually contains
> several newlines). The "start of line" metacharacter (^)
> matches only at the start of the string, while the "end of
> line" metacharacter ($) matches only at the end of the
> string, or before a terminating newline (unless
> CLASS="emphasis"
>>D> modifier is set). This is the same as
> Perl.
>
>>
> When this modifier is set, the "start of line" and "end of
> line" constructs match immediately following or immediately
> before any newline in the subject string, respectively, as
> well as at the very start and end. This is equivalent to
> Perl's /m modifier. If there are no "\n" characters in a
> subject string, or no occurrences of ^ or $ in a pattern,
> setting this modifier has no effect.
>
> >- >CLASS="emphasis"
>>s> (PCRE_DOTALL)
>- >
>
> If this modifier is set, a dot metacharacter in the pattern
> matches all characters, including newlines. Without it,
> newlines are excluded. This modifier is equivalent to Perl's
> /s modifier. A negative class such as [^a] always matches a
> newline character, independent of the setting of this
> modifier.
>
> >- >CLASS="emphasis"
>>x> (PCRE_EXTENDED)
>- >
>
> If this modifier is set, whitespace data characters in the
> pattern are totally ignored except when escaped or inside a
> character class, and characters between an unescaped #
> outside a character class and the next newline character,
> inclusive, are also ignored. This is equivalent to Perl's /x
> modifier, and makes it possible to include comments inside
> complicated patterns. Note, however, that this applies only
> to data characters. Whitespace characters may never appear
> within special character sequences in a pattern, for example
> within the sequence (?( which introduces a conditional
> subpattern.
>
> >- >CLASS="emphasis"
>>e>
>- >
>
> If this modifier is set, CLASS="function"
>>preg_replace()>
> does normal substitution of backreferences in the
> replacement string, evaluates it as PHP code, and uses the
> result for replacing the search string.
>
>>
> Only CLASS="function"
>>preg_replace()> uses this modifier;
> it is ignored by other PCRE functions.
>
>CLASS="note"
>>>>Note: >
> This modifier was not available in PHP3.
>
>
> >- >CLASS="emphasis"
>>A> (PCRE_ANCHORED)
>- >
>
> If this modifier is set, the pattern is forced to be
> "anchored", that is, it is constrained to match only at the
> start of the string which is being searched (the "subject
> string"). This effect can also be achieved by appropriate
> constructs in the pattern itself, which is the only way to
> do it in Perl.
>
> >- >CLASS="emphasis"
>>D> (PCRE_DOLLAR_ENDONLY)
>- >
>
> If this modifier is set, a dollar metacharacter in the pattern
> matches only at the end of the subject string. Without this
> modifier, a dollar also matches immediately before the final
> character if it is a newline (but not before any other
> newlines). This modifier is ignored if CLASS="emphasis"
>>m>
> modifier is set. There is no equivalent to this modifier in
> Perl.
>
> >- >CLASS="emphasis"
>>S>
>- >
>
> When a pattern is going to be used several times, it is
> worth spending more time analyzing it in order to speed up
> the time taken for matching. If this modifier is set, then
> this extra analysis is performed. At present, studying a
> pattern is useful only for non-anchored patterns that do not
> have a single fixed starting character.
>
> >- >CLASS="emphasis"
>>U> (PCRE_UNGREEDY)
>- >
>
> This modifier inverts the "greediness" of the quantifiers so
> that they are not greedy by default, but become greedy if
> followed by "?". It is not compatible with Perl. It can also
> be set by a (?U) modifier setting within the pattern.
>
> >- >CLASS="emphasis"
>>X> (PCRE_EXTRA)
>- >
>
> This modifier turns on additional functionality of PCRE that
> is incompatible with Perl. Any backslash in a pattern that
> is followed by a letter that has no special meaning causes
> an error, thus reserving these combinations for future
> expansion. By default, as in Perl, a backslash followed by a
> letter with no special meaning is treated as a literal.
> There are at present no other features controlled by this
> modifier.
>
> >- >CLASS="emphasis"
>>u> (PCRE_UTF8)
>- >
>
> This modifier turns on additional functionality of PCRE that
> is incompatible with Perl. Pattern strings are treated as
> UTF-8. This modifier is available from PHP 4.1.0 or greater
> on Unix and from PHP 4.2.3 on win32.
>
> >
>