Re: com php-src: fix negating an unsigned: Zend/zend_operators.h

On Mon, Sep 15, 2014 at 7:46 PM, Anatol Belski <ab@php.net> wrote: > Commit: e0ff5238c5d744509f93aaf914e23f17d51c5ae3 > Author: Anatol Belski <ab@php.net> Mon, 15 Sep 2014 17:48:15 > +0200 > Parents: 383a0773ff27cf57b94fe11d2f825b00cff88714 > Branches: master > > Link: > > http://git.php.net/?p=php-src.git;a=commitdiff;h=e0ff5238c5d744509f93aaf914e23f17d51c5ae3 > > Log: > fix negating an unsigned > > Changed paths: > M Zend/zend_operators.h > > > Diff: > diff --git a/Zend/zend_operators.h b/Zend/zend_operators.h > index 41342de..a50e65d 100644 > --- a/Zend/zend_operators.h > +++ b/Zend/zend_operators.h > @@ -1036,7 +1036,7 @@ static zend_always_inline void > fast_is_not_identical_function(zval *result, zval > /* buf points to the END of the buffer */ > #define _zend_print_signed_to_buf(buf, num, vartype, result) do { > \ > if (num < 0) { > \ > - _zend_print_unsigned_to_buf((buf), -(vartype)(num), vartype, > (result)); \ > + _zend_print_unsigned_to_buf((buf), (~((vartype)(num)) + 1), > vartype, (result)); \ > *--(result) = '-'; > \ > } else { > \ > _zend_print_unsigned_to_buf((buf), (num), vartype, (result)); > \ > Why this change? Unary minus of an unsigned value is a well-defined operation, see C89 3.1.2.5c5 or C99 6.2.5c9. Writing it this way seems much less clear to me. Unary minus is the operation that we mean here semantically. Nikita