# @eval[2**64-1]

#### vefatica

The second one below ... I don't understand it. Shouldn't it be 0xFFFFFFFFFFFFFFFF?
Code:
``````v:\> echo %@eval[2**64-1]
18446744073709551615

v:\> echo %@eval[2**64-1=x]
0x7FFFFFFFFFFFFFFF

v:\> echo %@eval[0x7FFFFFFFFFFFFFFF]
9223372036854775807``````

#### vefatica

To put it another way ...
Code:
``````v:\> echo %@eval[18446744073709551615=x]
0x7FFFFFFFFFFFFFFF

v:\> echo 0x%@convert[10,16,18446744073709551615]
0xFFFFFFFFFFFFFFFF``````

#### vefatica

It's 0/10. But doesn't that deal with what comes after a decimal point?

#### rconn

Hex values (like integer operators) are int64 (signed 64-bit) max.

#### vefatica

Hex values (like integer operators) are int64 (signed 64-bit) max.
Yeah, but 18446744073709551615 is 0xFFFFFFFFFFFFFFFF and treated an signed, that's -1.

0x7FFFFFFFFFFFFFFF is the largest positive signed int64, 9223372036854775807. I still can't figure out where it's coming from.

Code:
``````v:\> echo %@eval[18446744073709551615=x]
0x7FFFFFFFFFFFFFFF``````

#### vefatica

Is there a C function or WIN32 function that will turn 18446744073709551615 into 0x7FFFFFFFFFFFFFFF?

#### rconn

Yeah, but 18446744073709551615 is 0xFFFFFFFFFFFFFFFF and treated an signed, that's -1.

0x7FFFFFFFFFFFFFFF is the largest positive signed int64, 9223372036854775807. I still can't figure out where it's coming from.

It's coming from the RTL (_wtoi64).

#### vefatica

It's coming from the RTL (_wtoi64).
I see. _wcstoi64() does the same thing. I still think it's odd. 0 would be a better indication that something of an error (overflow) than _I64_MAX.

#### rconn

I'm not sure I understand why you think it's odd -- you're passing in an argument that's twice the maximum allowed size, and it's getting truncated (by the RTL).

Do you actually need to convert 64-bit values to hex?

#### vefatica

I'm not sure I understand why you think it's odd -- you're passing in an argument that's twice the maximum allowed size, and it's getting truncated (by the RTL).

Do you actually need to convert 64-bit values to hex?
1. It's just not very informative.

2. Occasionally.

#### rconn

Apparently not too occasionally, or you would have mentioned it a few years ago!

I'm afraid you're on your own here -- you can write your own function to do the > 2*64 hex conversions. (But it will not be easy.)

#### vefatica

Apparently not too occasionally, or you would have mentioned it a few years ago!

I'm afraid you're on your own here -- you can write your own function to do the > 2*64 hex conversions. (But it will not be easy.)
I already have @CONVERT, which gets it right.
Code:
``````v:\> echo %@eval[2**64-1]
18446744073709551615

v:\> echo %@convert[10,16,18446744073709551615]
FFFFFFFFFFFFFFFF``````

#### rconn

@CONVERT won't work with anything > 2**64, as it also uses int64 variables.

#### vefatica

@CONVERT won't work with anything > 2**64, as it also uses int64 variables.
Well I don't know how it does it but @CONVERT correctly turns 18446744073709551615 (which is less than 2**64) into FFFFFFFFFFFFFFFF. And it turns 18446744073709551614 into FFFFFFFFFFFFFFFE. And so on. Maybe @EVAL's "=x" should assume a positive number is desired and use @CONVERT.

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