PHP|BCMath: How to get bcscale value?

Update: As of PHP 7.3.0 you can just call the bcscale() function with no argument:

var_dump(bcscale()); // int(25)

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Prior to PHP 7.3.0 you could at first try to read the bcmath.scale INI setting, which defaults to 0:

$scale = ini_get('bcmath.scale');

Since calling bcscale() didn't change the bcmath.scale INI setting, the only way to get the current scale factor was using a workaround like that:

$scale = strlen(bcsqrt('2')) - 2;
var_dump($scale); // int(25)