php fgets()

Hi, I'm newbie in php and i would like to clearly understand how can i use: LENGTH in string fgets ( int fp [, int length]) "Returns a string of up to length - 1 bytes read from the file pointed to by fp. Reading ends when length - 1 bytes have been read, on a newline (which is included in the return value), or on EOF (whichever comes first). If no length is specified, the length defaults to 1k, or 1024 bytes." -Can i have an example of the differents way for reading file with fgets according to the differentes values of "length "? -why '4096' is used as length for reading a file line by line ? $fd = fopen ("/tmp/inputfile.txt", "r"); while (!feof ($fd)) { $buffer = fgets($fd, 4096); echo $buffer; } fclose ($fd); Is this any max for one line?? TIA. arnaud G.