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2022-11-03 cf8b7d374a 50467082c9 725cd4d2e4 eeb5461e76 Add casts to simplehash.h to silence C++ warnings.
* Add explicit casts in four places to simplehash.h
@ 2022-11-03 11:34 David Geier <geidav.pg@gmail.com>
0 siblings, 1 reply; 4+ messages in thread
From: David Geier @ 2022-11-03 11:34 UTC (permalink / raw)
To: PostgreSQL Developers <pgsql-hackers@lists.postgresql.org>
Hi hackers,
While working on an extension, I found that simplehash.h is missing
explicit casts in four places. Without these casts, compiling code
including simplehash.h yields warnings if the code is compiled with
-Wc++-compat.
PostgreSQL seems to mostly prefer omitting the explicit casts, however
there are many places where an explicit cast is actually used. Among
many others, see e.g.
bool.c:
state = (BoolAggState *) MemoryContextAlloc(agg_context,
sizeof(BoolAggState));
domains.c:
my_extra = (DomainIOData *) MemoryContextAlloc(mcxt,
sizeof(DomainIOData));
What about, while not being strictly necessary for PostgreSQL itself,
also adding such casts to simplehash.h so that it can be used in code
where -Wc++-compat is enabled?
Attached is a small patch that adds the aforementioned casts.
Thanks for your consideration!
--
David Geier
(ServiceNow)
Attachments:
0001-Add-explicit-casts-to-simplehash.h.patch (text/x-patch, 1.8K) download
From d2665b4065227ffa6efd37ee912e4add082869cb Mon Sep 17 00:00:00 2001
From: David Geier <geidav.pg@gmail.com>
Date: Thu, 3 Nov 2022 12:28:08 +0100
Subject: [PATCH] Add explicit casts to simplehash.h
Without these casts compilation yields warnings when compiling the
code with -Wc++-compat.
---
src/include/lib/simplehash.h | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/src/include/lib/simplehash.h b/src/include/lib/simplehash.h
index 329687c1a5..cdfae537a1 100644
--- a/src/include/lib/simplehash.h
+++ b/src/include/lib/simplehash.h
@@ -438,7 +438,7 @@ SH_CREATE(MemoryContext ctx, uint32 nelements, void *private_data)
#ifdef SH_RAW_ALLOCATOR
tb = SH_RAW_ALLOCATOR(sizeof(SH_TYPE));
#else
- tb = MemoryContextAllocZero(ctx, sizeof(SH_TYPE));
+ tb = (SH_TYPE *) MemoryContextAllocZero(ctx, sizeof(SH_TYPE));
tb->ctx = ctx;
#endif
tb->private_data = private_data;
@@ -448,7 +448,7 @@ SH_CREATE(MemoryContext ctx, uint32 nelements, void *private_data)
SH_COMPUTE_PARAMETERS(tb, size);
- tb->data = SH_ALLOCATE(tb, sizeof(SH_ELEMENT_TYPE) * tb->size);
+ tb->data = (SH_ELEMENT_TYPE *) SH_ALLOCATE(tb, sizeof(SH_ELEMENT_TYPE) * tb->size);
return tb;
}
@@ -493,7 +493,7 @@ SH_GROW(SH_TYPE * tb, uint64 newsize)
/* compute parameters for new table */
SH_COMPUTE_PARAMETERS(tb, newsize);
- tb->data = SH_ALLOCATE(tb, sizeof(SH_ELEMENT_TYPE) * tb->size);
+ tb->data = (SH_ELEMENT_TYPE *) SH_ALLOCATE(tb, sizeof(SH_ELEMENT_TYPE) * tb->size);
newdata = tb->data;
@@ -1059,7 +1059,7 @@ SH_STAT(SH_TYPE * tb)
double fillfactor;
uint32 i;
- uint32 *collisions = palloc0(tb->size * sizeof(uint32));
+ uint32 *collisions = (uint32 *) palloc0(tb->size * sizeof(uint32));
uint32 total_collisions = 0;
uint32 max_collisions = 0;
double avg_collisions;
--
2.34.1
* Re: Add explicit casts in four places to simplehash.h
@ 2022-11-03 14:50 Tom Lane <tgl@sss.pgh.pa.us>
parent: David Geier <geidav.pg@gmail.com>
0 siblings, 1 reply; 4+ messages in thread
From: Tom Lane @ 2022-11-03 14:50 UTC (permalink / raw)
To: David Geier <geidav.pg@gmail.com>; +Cc: PostgreSQL Developers <pgsql-hackers@lists.postgresql.org>
David Geier <geidav.pg@gmail.com> writes:
> What about, while not being strictly necessary for PostgreSQL itself,
> also adding such casts to simplehash.h so that it can be used in code
> where -Wc++-compat is enabled?
Seems reasonable, so done (I fixed one additional spot you missed).
The bigger picture here is that we do actually endeavor to keep
(most of) our headers C++ clean, but our tool cpluspluscheck misses
these problems because it doesn't try to use these macros.
I wonder whether there is a way to do better.
regards, tom lane
^ permalink raw reply [nested|flat] 4+ messages in thread
* Re: Add explicit casts in four places to simplehash.h
@ 2022-11-04 08:23 David Geier <geidav.pg@gmail.com>
parent: Tom Lane <tgl@sss.pgh.pa.us>
0 siblings, 1 reply; 4+ messages in thread
From: David Geier @ 2022-11-04 08:23 UTC (permalink / raw)
To: Tom Lane <tgl@sss.pgh.pa.us>; +Cc: PostgreSQL Developers <pgsql-hackers@lists.postgresql.org>
On 11/3/22 15:50, Tom Lane wrote:
> Seems reasonable, so done (I fixed one additional spot you missed).
Thanks!
> The bigger picture here is that we do actually endeavor to keep
> (most of) our headers C++ clean, but our tool cpluspluscheck misses
> these problems because it doesn't try to use these macros.
> I wonder whether there is a way to do better.
What about having a custom header alongside cpluspluscheck which
references all macros we care about?
We could start with the really big macros like the ones from
simplehash.h and add as we go.
I could give this a try if deemed useful.
--
David Geier
(ServiceNow)
^ permalink raw reply [nested|flat] 4+ messages in thread
* Re: Add explicit casts in four places to simplehash.h
@ 2022-11-04 13:25 Tom Lane <tgl@sss.pgh.pa.us>
parent: David Geier <geidav.pg@gmail.com>
0 siblings, 0 replies; 4+ messages in thread
From: Tom Lane @ 2022-11-04 13:25 UTC (permalink / raw)
To: David Geier <geidav.pg@gmail.com>; +Cc: PostgreSQL Developers <pgsql-hackers@lists.postgresql.org>
David Geier <geidav.pg@gmail.com> writes:
> On 11/3/22 15:50, Tom Lane wrote:
>> The bigger picture here is that we do actually endeavor to keep
>> (most of) our headers C++ clean, but our tool cpluspluscheck misses
>> these problems because it doesn't try to use these macros.
>> I wonder whether there is a way to do better.
> What about having a custom header alongside cpluspluscheck which
> references all macros we care about?
Can't see that that would help, because of the hand maintenance
required to make it useful.
regards, tom lane
^ permalink raw reply [nested|flat] 4+ messages in thread
end of thread, other threads:[~2022-11-04 13:25 UTC | newest]
Thread overview: 4+ messages (download: mbox mbox.gz follow: Atom feed)
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2022-11-03 11:34 Add explicit casts in four places to simplehash.h David Geier <geidav.pg@gmail.com>
2022-11-03 14:50 ` Tom Lane <tgl@sss.pgh.pa.us>
2022-11-04 08:23 ` David Geier <geidav.pg@gmail.com>
2022-11-04 13:25 ` Tom Lane <tgl@sss.pgh.pa.us>
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