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Date: Wed, 27 Sep 2023 14:38:16 +0100 (BST)
To: Larry Garfield <larry@garfieldtech.com>
cc: php internals <internals@lists.php.net>
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References: <a973a0f1-6a1d-0219-2059-823d2db497d4@mabe.berlin> <b09bda36-742f-4baa-9710-871c494d5d2c@app.fastmail.com>
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Subject: Re: [PHP-DEV] [RFC] [Discussion] Rounding Integers as int
From: derick@php.net (Derick Rethans)

On Tue, 26 Sep 2023, Larry Garfield wrote:

>  ceil and floor should 
> always return ints, unconditionally, because that's literally what 
> their purpose is.  But that RFC doesn't say that, which makes me quite 
> confused.

They can't do that. ceil(2.4e102) can't be repesented as an integer.

> Similarly, the BC shim would therefore be (float)ceil($x), not 
> ceil((float)$x), which... I don't think that would even do anything, 
> would it?

(float) $int *could* also do something:

$ php -dprecision=20 -r 'echo (float) 1152921504606846974;'

1152921504606846976

$ php -dprecision=20 -r 'var_dump(ceil((float) 1152921504606846974));'

double(1152921504606846976)

(see how the 74 changes into 76 at the end).

Integers in the ranges LONG_MAX to 2^53, and -2^53 to LONG_MIN can't be 
represented as whole numbers as float, and some precision is lost.

cheers,
Derick