note 92372 added to function.strcmp

One big caveat - strings retrieved from the backtick operation may be zero terminated (C-style), and therefore will not be equal to the non-zero terminated strings (roughly Pascal-style) normal in PHP. The workaround is to surround every `` pair or shell_exec() function with the trim() function. This is likely to be an issue with other functions that invoke shells; I haven't bothered to check. On Debian Lenny (and RHEL 5, with minor differences), I get this: ====PHP==== <?php $sz = pwd; $ps = "/var/www"; echo "Zero-terminated string:<br />sz = ".$sz."<br />str_split(sz) = "; print_r(str_split($sz)); echo "<br /><br />"; echo "Pascal-style string:<br />ps = ".$ps."<br />str_split(ps) = "; print_r(str_split($ps)); echo "<br /><br />"; echo "Normal results of comparison:<br />"; echo "sz == ps = ".($sz == $ps ? "true" : "false")."<br />"; echo "strcmp(sz,ps) = ".strcmp($sz,$ps); echo "<br /><br />"; echo "Comparison with trim()'d zero-terminated string:<br />"; echo "trim(sz) = ".trim($sz)."<br />"; echo "str_split(trim(sz)) = "; print_r(str_split(trim($sz))); echo "<br />"; echo "trim(sz) == ps = ".(trim($sz) == $ps ? "true" : "false")."<br />"; echo "strcmp(trim(sz),ps) = ".strcmp(trim($sz),$ps); ?> ====Output==== Zero-terminated string: sz = /var/www str_split(sz) = Array ( [0] => / [1] => v [2] => a [3] => r [4] => / [5] => w [6] => w [7] => w [8] => ) Pascal-style string: ps = /var/www str_split(ps) = Array ( [0] => / [1] => v [2] => a [3] => r [4] => / [5] => w [6] => w [7] => w ) Normal results of comparison: sz == ps = false strcmp(sz,ps) = 1 Comparison with trim()'d zero-terminated string: trim(sz) = /var/www str_split(trim(sz)) = Array ( [0] => / [1] => v [2] => a [3] => r [4] => / [5] => w [6] => w [7] => w ) trim(sz) == ps = true strcmp(trim(sz),ps) = 0 ---- Server IP: 209.41.74.194 Probable Submitter: 129.22.132.215 ---- Manual Page -- http://www.php.net/manual/en/function.strcmp.php Edit -- https://master.php.net/note/edit/92372 Del: integrated -- https://master.php.net/note/delete/92372/integrated Del: useless -- https://master.php.net/note/delete/92372/useless Del: bad code -- https://master.php.net/note/delete/92372/bad+code Del: spam -- https://master.php.net/note/delete/92372/spam Del: non-english -- https://master.php.net/note/delete/92372/non-english Del: in docs -- https://master.php.net/note/delete/92372/in+docs Del: other reasons-- https://master.php.net/note/delete/92372 Reject -- https://master.php.net/note/reject/92372 Search -- https://master.php.net/manage/user-notes.php