Re: Why does load_external_function() return PGFunction? - Mailing list pgsql-hackers

From Andres Freund
Subject Re: Why does load_external_function() return PGFunction?
Date
Msg-id 20180326201641.lwny3mb7girclach@alap3.anarazel.de
Whole thread Raw
In response to Re: Why does load_external_function() return PGFunction?  (Andres Freund <andres@anarazel.de>)
Responses Re: Why does load_external_function() return PGFunction?
List pgsql-hackers
On 2018-03-26 11:31:36 -0700, Andres Freund wrote:
> On 2018-03-26 11:14:03 -0400, Robert Haas wrote:
> > On Sat, Mar 24, 2018 at 4:33 PM, Andres Freund <andres@anarazel.de> wrote:
> > > I don't think it really changes the need, but it's worthwhile to note
> > > that gcc-8 warns about this now:
> > > /home/andres/src/postgresql/src/backend/postmaster/bgworker.c: In function ‘LookupBackgroundWorkerFunction’:
> > > /home/andres/src/postgresql/src/backend/postmaster/bgworker.c:1246:9: warning: cast between incompatible function
typesfrom ‘PGFunction’ {aka ‘long unsigned int (*)(struct FunctionCallInfoData *)’} to ‘void (*)(Datum)’ {aka ‘void
(*)(longunsigned int)’} [-Wcast-function-type]
 
> > >   return (bgworker_main_type)
> > 
> > That's probably going to mean we need, or at least want, to do
> > something about this at some point.  Warning-free compiles are
> > desirable.
> 
> Right. We can suppress those if we want, either by adding another cast,
> or by adding -Wno-cast-function-type. The latter wouldn't be entirely a
> bad idea, it seems to be a warning of very limited benefit.

I dug up a thread about the introduction of the warning:
https://gcc.gnu.org/ml/gcc-patches/2017-10/msg00423.html

Sounds like we should add something like
typedef void (*GenericFuncPtr) (void);
or such? Similar to what Tom proposed upthread.

- Andres


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