regex - PHP preg_match_all no character or not a certain character -

right test seems working avoiding characters don't want it's returning count of 2. know why, don't know how address it. problem last ? being excluded because actual match 2nd match (?+ it's not matching 3rd since there no "starting" character pattern, ?).

$pattern =  "/([^\w\d'\"`]\?[^\w\d'\"`])/"; $subject = "`test` = ? , `other` = (?+?)"; $count = preg_match_all($pattern, $subject, $matches); echo "count: $count\n"; // echoes 2 instead of 3 

basically, want count parameters used, match ? in $subject ? not surrounded letters, numbers, quotes, , ticks.

this actual pattern matters:

[^\w\d'\"'`] 

update: others, miken32's solution convert above pattern to:

(?=[^\w\d'\"'`]) 

try using lookahead assertion:

$pattern =  "/((?<=[^\w\d'\"`])\?(?=[^\w\d'\"`]))/"; 

it ahead without moving search forward.

edited add lookbehind assertion well.