Doc #77778 [Opn]: 0.0 is falsy but docs do not say -0.0 is falsy too

Edit report at https://bugs.php.net/bug.php?id=77778&edit=1 ID: 77778 Updated by: requinix@php.net Reported by: lewisje at alumni dot iu dot edu -Summary: -0.0 and 0.0 are distinct values. +Summary: 0.0 is falsy but docs do not say -0.0 is falsy too Status: Open Type: Documentation Problem -Package: Documentation problem +Package: *General Issues Operating System: CentOS 6 PHP Version: Irrelevant Block user comment: N Private report: N New Comment: If 0.0 and -0.0 are strictly identical then under what logic should (bool)0.0 be false and (bool)-0.0 be true? Seems silly to me that the docs should have to point out that both 0.0 and -0.0 are false, but I suppose it's an easy enough edit that it's not worth arguing about. Previous Comments: ------------------------------------------------------------------------ [2019-03-21 16:55:31] lewisje at alumni dot iu dot edu Description: ------------ --- From manual page: https://php.net/language.types.boolean --- Among the values listed as falsy is "the float 0.0 (zero)", but the float -0.0 is not listed; however, it is both falsy and distinct from 0.0: As ought to be pointed out in https://php.net/language.types.float, IEEE-754 floating-point arithmetic includes distinct 0.0 and -0.0 values; even though they will be treated as equal under strict equality, 1/0.0 is INF, while 1/-0.0 is -INF, again as in the IEEE-754 specification. Test script: --------------- <?php var_dump(1/0.0); // float(INF) var_dump(1/-0.0); // float(-INF) var_dump(-0.0 === 0.0); // bool(true) var_dump((bool)-0.0); // bool(false) ?> Expected result: ---------------- Based on the literal documentation, (bool)-0.0 ought to be true. Actual result: -------------- (bool)-0.0 is false, and as the other statements show, -0.0 can be distinguished from 0.0, which means that it is another falsy value. ------------------------------------------------------------------------ -- Edit this bug report at https://bugs.php.net/bug.php?id=77778&edit=1