Обсуждение: Pgxs - How to reference another extension

Hi,

I am trying to create an extension that delegates some calls to btree_gist functions:

DirectFunctionCall5Coll(
                gbt_text_consistent, …other arguments);

Basic PGXS Makefile does not work - I get linker error:

Undefined symbols for architecture arm64:
  "_gbt_text_consistent", referenced from:


Anyone could provide me with some hints?

—
Michal

> On 11 Mar 2024, at 11:41, Michał Kłeczek <michal@kleczek.org> wrote:
>
> Hi,
>
> I am trying to create an extension that delegates some calls to btree_gist functions:
>
> DirectFunctionCall5Coll(
>                gbt_text_consistent, …other arguments);
>
> Basic PGXS Makefile does not work - I get linker error:
>
> Undefined symbols for architecture arm64:
>  "_gbt_text_consistent", referenced from:
>
>
> Anyone could provide me with some hints?

I’ve added:
PG_LDFLAGS += -L$(shell $(PG_CONFIG) --pkglibdir) -lbtree_gist

to Makefile and I get the following:

ld: library 'btree_gist' not found
clang: error: linker command failed with exit code 1 (use -v to see invocation)

Note that I am on Mac and btree_gist.dylib is present in $(pg_config —pkglibdir)

—
Michal

On Mon, 11 Mar 2024 at 13:26, Michał Kłeczek <michal@kleczek.org> wrote:
>
>
> > On 11 Mar 2024, at 11:41, Michał Kłeczek <michal@kleczek.org> wrote:
> >
> > Hi,
> >
> > I am trying to create an extension that delegates some calls to btree_gist functions:
> >
> > DirectFunctionCall5Coll(
> >                gbt_text_consistent, …other arguments);
> >
> > Basic PGXS Makefile does not work - I get linker error:
> >
> > Undefined symbols for architecture arm64:
> >  "_gbt_text_consistent", referenced from:
> >
> >
> > Anyone could provide me with some hints?
>
> I’ve added:
> PG_LDFLAGS += -L$(shell $(PG_CONFIG) --pkglibdir) -lbtree_gist

You can try FunctionCall5Coll() or OidFunctionCall5Coll() functions.

OidFunctionCall5Coll() calls fmgr_info() and FunctionCall5Coll(). What
you only need is Oid of the target function.

FunctionCall5Coll() can be useful and used when you have a cache
variable of the function, where you store previously calculated
FmgrInfo.

--
Artur

On 3/11/24 09:48, Michał Kłeczek wrote:
> 
> 
>> On 11 Mar 2024, at 14:08, Artur Zakirov <zaartur@gmail.com> wrote:
>>
>> On Mon, 11 Mar 2024 at 13:26, Michał Kłeczek <michal@kleczek.org 
>> <mailto:michal@kleczek.org>> wrote:
>>>
>>>
>>>> On 11 Mar 2024, at 11:41, Michał Kłeczek <michal@kleczek.org> wrote:
>>>>
>>>> Hi,
>>>>
>>>> I am trying to create an extension that delegates some calls to 
>>>> btree_gist functions:
>>>>
>>>> DirectFunctionCall5Coll(
>>>>               gbt_text_consistent, …other arguments);
>>>>
>>>> Basic PGXS Makefile does not work - I get linker error:
>>>>
>>>> Undefined symbols for architecture arm64:
>>>> "_gbt_text_consistent", referenced from:
>>>>
>>>>
>>>> Anyone could provide me with some hints?
>>>
>>> I’ve added:
>>> PG_LDFLAGS += -L$(shell $(PG_CONFIG) --pkglibdir) -lbtree_gist
>>
>> You can try FunctionCall5Coll() or OidFunctionCall5Coll() functions.
>>
>> OidFunctionCall5Coll() calls fmgr_info() and FunctionCall5Coll(). What
>> you only need is Oid of the target function.
> 
> What I am trying to do is wrapping and decoration of gbt_text_consistent 
> function.
> The reason I want to use DirectFunctionCall5Col is that other variants 
> require catalog lookup
> as I don’t have old of the wrapped function.
> The lookup itself is problematic as the only piece of information I have 
> is the strategy number.
> What’s more - the result of the lookup should be cached in fn_extra and 
> that makes things even more complex.
> 
> Is there any way to simply link against another extension library?


I used this successfully in the past with postgis:

postgis_libdir := $(shell pg_config --pkglibdir)
postgis_libver := $(shell ls -1 $(postgis_libdir) | grep "^postgis")
SHLIB_LINK += -L$(postgis_libdir) -l:$(postgis_libver) -llwgeom

HTH,

-- 
Joe Conway
PostgreSQL Contributors Team
RDS Open Source Databases
Amazon Web Services: https://aws.amazon.com