From: Nathan Thatcher <n8thatcher@gmail.com>
To: pgsql-interfaces@postgresql.org
Subject: User Defined C Function
Date: Thu, 1 May 2008 17:18:29 -0600
Message-ID: <d9c17fb40805011618j6cdd6719nf4a1bff6eb4582a5@mail.gmail.com> (raw)
I have been creating some user defined C functions using minGW and
postgreSQL 8.3. Everything works great when I use integers,
timestamps, points, etc. I have compiled, linked, created, and tested
multiple function and aggregates.
The problem occurs when I have a text parameter and need to use
PG_GETARG_TEXT_P(n). The code compiles just fine but linking fails.
Here is an example:
#include "postgres.h"
#include "fmgr.h"
PG_MODULE_MAGIC;
PG_FUNCTION_INFO_V1(function);
Datum
function(PG_FUNCTION_ARGS)
{
text *t = PG_GETARG_TEXT_P(1);
int32 i = PG_GETARG_INT32(0);
PG_RETURN_INT32(i+1);
}
The error:
X)function_name.o:function_name.c: undefined reference to `pg_detoast_datum'
If I comment out the text *t line then it compiles, links, and
executes just fine.
The problem (I am assuming it is the same problem) also manifests
itself when I make a call to palloc. I get 2 errors
X) finalagent.o:finalagent.c: undefined reference to
`_imp__CurrentMemoryContext'
X) finalagent.o:finalagent.c: undefined reference to `MemoryContextAlloc'
Some people have said that this error should just be ignored and it
will sort itself out at run-time. That sounds swell but how do I get
my linker to ignore these errors?
Other people have said that pg_detoast_datum is a backend function and
shouldn't be referenced at all, but it is right there in fmgr.h which
is obviously required for creating functions under the V1 calling
convention.
For reference, I am on Windows XP SP2. I installed postgreSQL 8.3 from
the msi and selected to include the Development components (Include
Files, Library Files, Tools and utilities). The compiler is including
the following directories:
C:\PostgreSQL\8.3\include
C:\PostgreSQL\8.3\include\server
C:\PostgreSQL\8.3\include\server\port\win32"
I added both C:\PostgreSQL\8.3\lib and C:\PostgreSQL\8.3\bin to my
linker hoping that maybe it would work. It didn't.
Any information, insight, tips, or criticism would be welcomed and appreciated.
-Subordin8
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To: pgsql-interfaces@postgresql.org
Cc: n8thatcher@gmail.com
Subject: Re: User Defined C Function
In-Reply-To: <d9c17fb40805011618j6cdd6719nf4a1bff6eb4582a5@mail.gmail.com>
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