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Message-ID: <05b7e019-27d4-e6a9-2088-f712c22317a9@mabe.berlin>
Date: Sun, 21 May 2023 07:16:35 +0200
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To: PHP internals <internals@lists.php.net>
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Subject: rounding integers
From: marc@mabe.berlin (Marc)

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Hi all,

The "round" function supports rounding to significant digits before the 
decimal point which can be very helpful

but unfortunately it's handling everything as floating point numbers 
which in the end can lead to inaccurate results.

     printf("%d\n", round(987654321098765432, -1) // 987654321098765440 
instead of 987654321098765430

To be fair it's also documented as such:

 > round — Rounds a float

round(int|float $num, int $precision = 0, int $mode = 
PHP_ROUND_HALF_UP): float


I would like to propose to change this function to keep the given type 
and proper handle integers as well:

 > round — Rounds a number

/** @template T of int|float */

round(T $num, int $precision = 0, int $mode = PHP_ROUND_HALF_UP): T


Do you think this could be an acceptable BC-break or should this be a 
different function?


Thanks,

Marc

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