2007-08-06 03:27:17

by Al Viro

Subject: [PATCH] take sched_debug.c out of nasal demon territory

C99 6.10.3[11]: preprocessing directive within the argument list
of macro invocation => undefined behaviour. Don't do that...

Signed-off-by: Al Viro <[email protected]>
---
diff --git a/kernel/sched_debug.c b/kernel/sched_debug.c
index 1c61e53..8421b93 100644
--- a/kernel/sched_debug.c
+++ b/kernel/sched_debug.c
@@ -36,24 +36,24 @@ print_task(struct seq_file *m, struct rq *rq, struct task_struct *p, u64 now)
else
SEQ_printf(m, " ");

- SEQ_printf(m, "%15s %5d %15Ld %13Ld %13Ld %9Ld %5d "
- "%15Ld %15Ld %15Ld %15Ld %15Ld\n",
+ SEQ_printf(m, "%15s %5d %15Ld %13Ld %13Ld %9Ld %5d ",
p->comm, p->pid,
(long long)p->se.fair_key,
(long long)(p->se.fair_key - rq->cfs.fair_clock),
(long long)p->se.wait_runtime,
(long long)(p->nvcsw + p->nivcsw),
- p->prio,
+ p->prio);
#ifdef CONFIG_SCHEDSTATS
+ SEQ_printf(m, "%15Ld %15Ld %15Ld %15Ld %15Ld\n",
(long long)p->se.sum_exec_runtime,
(long long)p->se.sum_wait_runtime,
(long long)p->se.sum_sleep_runtime,
(long long)p->se.wait_runtime_overruns,
- (long long)p->se.wait_runtime_underruns
+ (long long)p->se.wait_runtime_underruns);
#else
- 0LL, 0LL, 0LL, 0LL, 0LL
+ SEQ_printf(m, "%15Ld %15Ld %15Ld %15Ld %15Ld\n",
+ 0LL, 0LL, 0LL, 0LL, 0LL);
#endif
- );
}

static void print_rq(struct seq_file *m, struct rq *rq, int rq_cpu, u64 now)

2007-08-06 15:51:39

by Jan Engelhardt

Subject: Re: [PATCH] take sched_debug.c out of nasal demon territory

On Aug 6 2007 04:26, Al Viro wrote:
>
> C99 6.10.3[11]: preprocessing directive within the argument list
>of macro invocation => undefined behaviour. Don't do that...

String concatenation ("a" "b") is not a preprocessing directive.

$ gcc -E test.c
# 1 "test.c"
# 1 "<built-in>"
# 1 "<command line>"
# 1 "test.c"
printf("a" "b");

(If it was, the "a" "b" would have already been joined.)


Jan
--

2007-08-06 17:05:25

by Al Viro

Subject: Re: [PATCH] take sched_debug.c out of nasal demon territory

On Mon, Aug 06, 2007 at 05:51:29PM +0200, Jan Engelhardt wrote:
>
> On Aug 6 2007 04:26, Al Viro wrote:
> >
> > C99 6.10.3[11]: preprocessing directive within the argument list
> >of macro invocation => undefined behaviour. Don't do that...
>
> String concatenation ("a" "b") is not a preprocessing directive.

It is not, but #ifdef definitely is.

2007-08-08 09:17:28

by Cong Wang

Subject: Re: [PATCH] take sched_debug.c out of nasal demon territory

On Mon, Aug 06, 2007 at 05:51:29PM +0200, Jan Engelhardt wrote:
>
>On Aug 6 2007 04:26, Al Viro wrote:
>>
>> C99 6.10.3[11]: preprocessing directive within the argument list
>>of macro invocation => undefined behaviour. Don't do that...
>
>String concatenation ("a" "b") is not a preprocessing directive.
>
>$ gcc -E test.c
># 1 "test.c"
># 1 "<built-in>"
># 1 "<command line>"
># 1 "test.c"
>printf("a" "b");
>
>(If it was, the "a" "b" would have already been joined.)
>

Yes. According to C99 5.1.1.2, string concatenation is done in Phase 6,
that's after preprocessing.

Regards.

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U ack!