problems / mistake in pack () and unpack() ???

hello i use the function pack() and unpack() i have following question:

    $content = -2147483647;
    $binarydata = pack("V", $content);

    ...(fwrite in file)
    ...(fread from file)

    $bin_str = fread ($handle, 4);
    $ascii_array = unpack("V", $bin_str);
    $ascii_str = $ascii_array[1];

it makes no difference if i use the "V", the "l" or the "L" flag ! every flag works the same...output is '-2147483647' but from the php page i get this: l -- Long-Typ with sign (always 32 Bit, Byte-sequenz maschine depent) L -- Long-Typ without sign (always 32 Bit, Byte-sequenz maschine depent) V -- Long-Typ without sign (always 32 Bit, little endian) why is it so ? what happends ? thank you