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Found 1 result

  1. I dont understand arrays in PHP and its necessary to finally fess up and ask for help. It seems so trivial,, but I've spent Whole DAYS trying to make sense of this. (I came from assemble language programming). I am receiving UDP packets of a known size. in this case, 4 bytes of binary data. It gets unpacked ( I dont know why. I cut and pasted this simple parser from an example). All I want is the array[0] byte. I'm trying to avoid complex loops and pointers. // First lets grab a data packet and put our few bytes into the variable $buf while(1) { socket_recvfrom($socket, $buf, 16, 0, $from, $port); // Easy! but the UDP data in $buf is binary not useful like this. //Convert to array of decimal values $array = unpack("C*", $buf); // 'C' tells unpack to make unsigned chars from the binary. //Convert decimal values to ASCII characters: $chr_array = array(); // wait a second. What is happening here? for ($i = 0; $i < count($array); $i++) { $chr_array[] = chr($array[$i]); // Whats going on here? Anyone? } // So now I can assume the first byte of this $chr_array[] is my prize, right? $mychr = chr_array[0]; // Nope. Looking at $chr_array[0] either reveals a zero or the actual word "Array", depending on how late I've stayed up. print_r($array); // This is my debugger. It shows SOMETHING is working. echo "Received $mychr from remote $address $from and remote port $port" . PHP_EOL; } socket_close($sock); Output of above code... assuming the value read was 60 decimal: Array ( [1] => 60 [2] => 0 [3] => 0 [4] => 0 ) Received 0 from remote address nnn.nnn.nnn.nnn and remote port 8888 So print_r knows what to do, the last line of my code doesn't. Any help would be appreciated, as this goes to the heart of my issue of being mystified by how PHP makes and processes arrays. Its clearly not just a string of numbers. I'm trying to pull ONE printable number from that buffer. Halp!
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