Re: [PATCH i-g-t 3/5] lib/core: Avoid unused result in backtrace printing

Chris Wilson
2017-11-22T17:52:45Z

Quoting Tvrtko Ursulin (2017-11-22 17:44:23)
>
> Ping on this one - do we want to squash these compile warnings, yes? :)

Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>

> On 08/11/2017 12:06, Tvrtko Ursulin wrote:
> > From: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
> >
> > Add helpers for direct write to stderr to consolidate the code
> > and avoid the unused result warning in build.
> >
> > v2: Use igt_ignore_warn since it is questionable whether igt_assert
> > is safe in signal handlers. (Chris Wilson)
> >
> > Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
> > ---
> > lib/igt_core.c | 23 ++++++++++++++++-------
> > 1 file changed, 16 insertions(+), 7 deletions(-)
> >
> > diff --git a/lib/igt_core.c b/lib/igt_core.c
> > index 538a4472e209..e866bf995872 100644
> > --- a/lib/igt_core.c
> > +++ b/lib/igt_core.c
> > @@ -1239,7 +1239,7 @@ static const char hex[] = "0123456789abcdef";
> > static void
> > xputch(int c)
> > {
> > - write(STDERR_FILENO, (const void *) &c, 1);
> > + igt_ignore_warn(write(STDERR_FILENO, (const void *) &c, 1));
> > }
> >
> > static int
> > @@ -1384,13 +1384,23 @@ xprintf(const char *fmt, ...)
> > va_end(ap);
> > }
> >
> > +static void __write_stderr(const char *str, size_t len)
> > +{
> > + igt_ignore_warn(write(STDERR_FILENO, str, len));
> > +}
> > +
> > +static void write_stderr(const char *str)
> > +{
> > + __write_stderr(str, strlen(str));
> > +}
> > +
> > static void print_backtrace_sig_safe(void)
> > {
> > unw_cursor_t cursor;
> > unw_context_t uc;
> > int stack_num = 0;
> >
> > - write(STDERR_FILENO, "Stack trace: \n", 15);
> > + write_stderr("Stack trace: \n");
> >
> > unw_getcontext(&uc);
> > unw_init_local(&cursor, &uc);
> > @@ -1899,11 +1909,10 @@ static void fatal_sig_handler(int sig)
> > continue;
> >
> > if (handled_signals[i].name_len) {
> > - igt_assert_eq(write(STDERR_FILENO, "Received signal ", 16),
> > - 16);
> > - igt_assert_eq(write(STDERR_FILENO, handled_signals[i].name, handled_signals[i].name_len),
> > - handled_signals[i].name_len);
> > - igt_assert_eq(write(STDERR_FILENO, ".\n", 2), 2);
> > + write_stderr("Received signal ");
> > + __write_stderr(handled_signals[i].name,
> > + handled_signals[i].name_len);

You could argue that we can kill name_len now that write_stderr makes it
tidier to do without.
-Chris