note 77548 added to function.fread

Having tried to reliably transfer large amounts of binary data over a latent network, I found out that fread()/fwrite() should never be trusted to read/write the whole block with the exact length specified, even in blocking mode, even for small block lengths. I came up with these two functions, fully-replaceable and reliable alternatives of fread()/fwrite() in a socket context: <?php function fullwrite ($sd, $buf) { $total = 0; $len = strlen($buf); while ($total < $len && ($written = fwrite($sd, $buf))) { $total += $written; $buf = substr($buf, $written); } return $total; } function fullread ($sd, $len) { $ret = ''; $read = 0; while ($read < $len && ($buf = fread($sd, $len - $read))) { $read += strlen($buf); $ret .= $buf; } return $ret; } ?> The functions are "greedy", i.e. trying to read/write as much data as possible at once. If the call to fread()/fwrite() reads/writes less than expected, then the next iteration eats up the remainder. Very smart as only the largest possible chunks are read/written. Only in case of a broken pipe fullread()/fullwrite() return less than the specified length. Otherwise it is guaranteed that upon termination strlen(fullread($sd, $len)) == $len and fullwrite($sd, $buf) == strlen($buf) Works perfectly with a socket descriptor returned from stream_socket_client() or fsockopen(). Greetings from Rousse, Bulgaria. ---- Server IP: 217.75.128.29 Probable Submitter: 212.25.59.124 ---- Manual Page -- http://www.php.net/manual/en/function.fread.php Edit -- https://master.php.net/note/edit/77548 Del: integrated -- https://master.php.net/note/delete/77548/integrated Del: useless -- https://master.php.net/note/delete/77548/useless Del: bad code -- https://master.php.net/note/delete/77548/bad+code Del: spam -- https://master.php.net/note/delete/77548/spam Del: non-english -- https://master.php.net/note/delete/77548/non-english Del: in docs -- https://master.php.net/note/delete/77548/in+docs Del: other reasons-- https://master.php.net/note/delete/77548 Reject -- https://master.php.net/note/reject/77548 Search -- https://master.php.net/manage/user-notes.php