Thread: tableam.h fails cpluspluscheck

Using Apple's clang as c++ compiler:

In file included from /tmp/cpluspluscheck.KejiIw/test.cpp:3:
./src/include/access/tableam.h:144:16: error: typedef redefinition with different types ('void (*)(Relation, HeapTuple,
Datum*, bool *, bool, void *)' (aka 'void (*)(RelationData *, HeapTupleData *, unsigned long *, bool *, bool, void *)')
vs'IndexBuildCallback') 
typedef void (*IndexBuildCallback) (Relation index,
               ^
./src/include/access/tableam.h:36:8: note: previous definition is here
struct IndexBuildCallback;
       ^

(there are some cascading errors, but this is the important one)

Kinda looks like you can't get away with using "struct" on a forward
declaration of something that is not actually a struct type.

            regards, tom lane

Hi,

On 2019-05-30 14:01:00 -0400, Tom Lane wrote:
> Using Apple's clang as c++ compiler:
> 
> In file included from /tmp/cpluspluscheck.KejiIw/test.cpp:3:
> ./src/include/access/tableam.h:144:16: error: typedef redefinition with different types ('void (*)(Relation,
HeapTuple,Datum *, bool *, bool, void *)' (aka 'void (*)(RelationData *, HeapTupleData *, unsigned long *, bool *,
bool,void *)') vs 'IndexBuildCallback')
 
> typedef void (*IndexBuildCallback) (Relation index,
>                ^
> ./src/include/access/tableam.h:36:8: note: previous definition is here
> struct IndexBuildCallback;
>        ^
> 
> (there are some cascading errors, but this is the important one)
> 
> Kinda looks like you can't get away with using "struct" on a forward
> declaration of something that is not actually a struct type.

Ugh. Odd that only C++ compilers complain. I just removed the typedef,
it's not needed anymore (it used to be neccessary before moving
IndexBuildCallback's definition to tableam.h - but was wrong then too,
just cpluspluscheck didn't notice).

Pushed the obvious fix.

Greetings,

Andres Freund

Andres Freund <andres@anarazel.de> writes:
> On 2019-05-30 14:01:00 -0400, Tom Lane wrote:
>> Kinda looks like you can't get away with using "struct" on a forward
>> declaration of something that is not actually a struct type.

> Ugh. Odd that only C++ compilers complain. I just removed the typedef,
> it's not needed anymore (it used to be neccessary before moving
> IndexBuildCallback's definition to tableam.h - but was wrong then too,
> just cpluspluscheck didn't notice).

Cool, thanks.

            regards, tom lane