[webkit-dev] Reminder regarding formatting uint64_t

[Ryosuke Niwa]

We should probably stop using these formatting strings in favor of
makeString by making *LOG* functions to use makeString behind the scene.

See https://trac.webkit.org/changeset/242014 for example.

- R. Niwa

On Wed, Feb 27, 2019 at 2:36 PM Michael Catanzaro <mcatanzaro at igalia.com>
wrote:

> Hi,
>
> For the past several years, I've been regularly fixing -Wformat
> warnings that look like this:
>
> ../../Source/WebKit/WebProcess/WebPage/WebPage.cpp:3148:46: warning:
> format ‘%llu’ expects argument of type ‘long long unsigned
> int’, but argument 6 has type ‘uint64_t’ {aka ‘long unsigned
> int’} [-Wformat=]
>          RELEASE_LOG_ERROR(ProcessSuspension, "%p - WebPage
> (PageID=%llu) - LayerTreeFreezeReason::ProcessSuspended was set when
> removing LayerTreeFreezeReason::PageTransition; current reasons are %d",
>
>
> ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
>              this, m_pageID, m_LayerTreeFreezeReasons.toRaw());
>                    ~~~~~~~~
>
> Problem is that uint64_t is long long unsigned int on Mac, but only
> long unsigned int on Linux. It can't be printed with %llu, so please
> use PRIu64 instead. E.g.:
>
> LOG("%llu", pageID); // wrong
> LOG("%" PRIu64, pageID); // correct
>
> This is good to keep in mind for any sized integer types, but uint64_t
> in particular since this is what causes problems for us in practice.
>
> Thanks,
>
> Michael
>
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