On Thu, Jan 13 2022, Han-Wen Nienhuys wrote:
> On Thu, Jan 13, 2022 at 12:38 PM Ævar Arnfjörð Bjarmason
> <avarab@xxxxxxxxx> wrote:
>> Change code added in 1ae2b8cda84 (reftable: add merged table view,
>> 2021-10-07) to be compatible with older versions of AIX's IBM xlc
>> compiler. Version V12.1 of it (on gcc111.fsffrance.org) will hard
>> error with:
>>
>> "reftable/merged_test.c", line 211.19: 1506-196 (S) Initialization between types "char*" and "struct reftable_ref_record" is not allowed.
>> "reftable/merged_test.c", line 212.19: 1506-196 (S) Initialization between types "unsigned long long" and "struct reftable_ref_record" is not allowed.
>> "reftable/merged_test.c", line 213.19: 1506-196 (S) Initialization between types "enum {...}" and "struct reftable_ref_record" is not allowed.
>> "reftable/merged_test.c", line 214.19: 1506-196 (S) Initialization between types "unsigned char*" and "struct reftable_ref_record" is not allowed.
>> "reftable/merged_test.c", line 349.19: 1506-196 (S) Initialization between types "char*" and "struct reftable_log_record" is not allowed.
>> "reftable/merged_test.c", line 350.19: 1506-196 (S) Initialization between types "unsigned long long" and "struct reftable_log_record" is not allowed.
>> "reftable/merged_test.c", line 351.19: 1506-196 (S) Initialization between types "enum {...}" and "struct reftable_log_record" is not allowed.
>
> Weird. What C standard does xlc implement?
I don't know. Your guess (and searching through IBM's website) is as
good as mine.
AFAICT it mostly implements the C99 semantics, but doesn't grok the
interpolation of structs-within-structs
>> Perhaps there's a better way to do this, but just duplicating the
>> earlier struct values declared earlier in these functions works, and
>> is probably the least bad solution.
>
> I'd rather not duplicate anything. Can't you do
>
> struct foobar *want = { &r[0], &r[2] .. }
Maybe I'm just not understanding what you mean, but this:
struct reftable_ref_record *want = {
&r2[0],
&r1[1],
&r3[0],
&r3[1],
};
Gives us the predictable compiler error on gcc/clang, nevermind
xlc. Turn that into:
struct reftable_ref_record want[] = {
&r2[0],
&r1[1],
&r3[0],
&r3[1],
};
And you can get gcc/clang to emulate what that xlc version (mis)parses
that as. I.e. it takes it as a reference to the nth element in that
struct.
