winmm: Sign-compare warning fix (Resend)

James Mckenzie jjmckenzie51 at
Fri Dec 12 10:51:35 CST 2008

Michael Karcher <wine at> at: Dec 12, 2008 9:23 AM (MST) wrote about: RE: winmm: Sign-compare warning fix (Resend)
>Am Freitag, den 12.12.2008, 09:07 -0700 schrieb James Mckenzie:
>> >  unsigned int i;
>> >
>> >  ...
>> >
>> >  for (i = sizeof(foo) / sizeof(foo[0]) - 1; ~i; --i)
>> >
>> >Tested? No.
>> >Readable? Don't ask me... :-)
>> I understood it, but is not the goal to avoid the use of C++ constructs in WINE code?
>There is no C++ construct in that code. Still i-- would do the same and
>is more idiomatic C.
>> The real question is why convert a for loop to a while loop?
>After the last iteration, the --i (or i--) overflows. In a for loop, the
>step statement (the third statement in the loop head) is always executed
>before the test (the second statement in the loop head), so there is no
>way to prevent the overflow. While this is not a problem per se, as
>overflow of unsigned variables is well-defined, testing for "overflow
>just happended" tends to be more confusing to the readers than testing
>for "is at the end".
>If you use a while loop instead, you can arrange the test to be executed
>*before* the step is performed, so you have to abort on "i == 0 just
>finished" insted of "i == ~0U is next", the former being easier to
This is a definite improvement.  Glad you caught it and thank you for the lesson in the use of structures vice arrays.  I'll take a close look at the code and your change this weekend.  I was caught by the use of sizeof(array[0]) vice sizeof(struct[0]), which do yeild different results.

James McKenzie

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