Bitwise OR problem

[jeffg]

I have this code, with an echo test statement:

		$jar_mask = $from_ar[5] | $to_ar[5];		echo "jar_mask: $jar_mask; from_ar[5]: {$from_ar[5]}; to_ar[5]: {$to_ar[5]}<br>";

And this is what I get in the output:

jar_mask: 72; from_ar[5]: 32; to_ar[5]: 4

When I last looked, bit5 (32) or'd with bit2 (4) gave bit5|bit2, not bit7|bit3. The result should be 36, not 72.Please tell me I am not going crazy, and I am doing something wrong?Uh-oh: if I change that to

		$jar_mask = intval($from_ar[5]) | intval($to_ar[5]);

then it works. But please could you explain why the first one doesn't. Is it doing some weird string thing?

[justsomeguy]

Yeah, it's probably doing a string conversion. 72 in binary is 1001000, so it's masking the 8 and 64 bits. I'm not sure why those are both double (left-shifted 1 place) what they should be, but I would assume it's a conversion. But, when you're working with bits, it's always best to explicitly cast all of your variables so that you know what the data types are.

[jeffman]

Type conversion in javascript stinks. So many workarounds. Everything seems like a kludge. Wouldn't you love an "as" operator or a simple equivalent?

[jeffg]

Type conversion in javascript stinks.

Umm. I assume that was a slip and you meant PHP? Thanks for the comments. It had me scratching my head till I guessed what was happening.