By default, the quantifiers are "greedy", that is, they match as much as possible (up to the maximum number of permitted times), without causing the rest of the pattern to fail. The classic example of where this gives problems is in trying to match comments in C programs. These appear between the sequences /* and */ and within the sequence, individual * and / characters may appear. An attempt to match C comments by applying the pattern /\*.*\*/ to the string /* first comment */ not comment /* second comment */ fails, because it matches the entire string due to the greediness of the .* item.

However, if a quantifier is followed by a question mark, then it ceases to be greedy, and instead matches the minimum number of times possible, so the pattern /\*.*?\*/ does the right thing with the C comments. The meaning of the various quantifiers is not otherwise changed, just the preferred number of matches. Do not confuse this use of question mark with its use as a quantifier in its own right. Because it has two uses, it can sometimes appear doubled, as in \d??\d which matches one digit by preference, but can match two if that is the only way the rest of the pattern matches.

If the PCRE_UNGREEDY option is set (an option which is not available in Perl) then the quantifiers are not greedy by default, but individual ones can be made greedy by following them with a question mark. In other words, it inverts the default behaviour.

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<?php
$dopuszczalne_znaki = '/^[a-zA-Z]s[a-zA-Z-]+$/D';
?>
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Dopuszczamy gdy jest jedna spacja(miedzy imieniem i nazwiskiem) oraz 0 lub 1 myślink w nazwisku:) jeszcze możesz wzbogacić i polskie znaki

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<?php
$dopuszczalne_znaki = '/^[a-zążźćńęłA-ZĄŻŹĆŃĘŁ]s[a-zA-Z-]+$/D';
?>
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