php - read single byte as an unsigned byte

Solution:

The unpack format string is actually likecode [repeater] [name], separated by forward slashes. For example,Clength. The output array will be associative and keyed by name, with repeated fields having a numeric suffix appended, starting at 1. E.g. the output keys forC2length will belength1 andlength2.

The documentation is not super-clear about this.

So when you don't specify any name, it just appends the numeric suffix, starting at 1. So the length you are looking for is$lenarr[1].

But you should try this instead:

$v = unpack('Clength', "\x04");
var_export($v);  // array('length' => 4)
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Here are some other examples:

unpack('C2length', "\x04\x03");
// array ( 'length1' => 4, 'length2' => 3, );

unpack('Clength/Cwidth', "\x04\x03");
// array ( 'length' => 4, 'width' => 3, );
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Also, in php you can't generally use array-access notation on an expression--you need to use it on the variable directly. Sofunctioncall()[0] won't work, you need$v = functioncall(); $v[0]. This is a php wart.

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