Compiling extension C with MingW in windows, Error...

On Fri, Sep 3, 2010 at 5:31 AM, Edwin Quijada
<listas_quijada@hotmail.com> wrote:

Hi, I am tryng to compile a C extension in windows using Minigw but always I
get the same error

C:\Program Files\PostgreSQL\8.3\share\exte_c>C:\mingw\bin\gcc -shared -o
pg2.dll
 pg2.o
pg2.o:pg2.c:(.text+0x86): undefined reference to
`_imp__CurrentMemoryContext'
pg2.o:pg2.c:(.text+0x92): undefined reference to `MemoryContextAlloc'
collect2: ld returned 1 exit status

This error is just when it links.

You need to link against postgres.exe to get access to these symbols.
I don't recall if the mingw linker allows you to just specify the EXE
file these days, but I think it does. If not, you'll need to create an
import library from the EXE and link to that (the binary distribution
only ships with import libraries for MSVC, but mingw can't use
standard windows import libraries, so you need to create your own
there)

--
 Magnus Hagander
 Me: http://www.hagander.net/
 Work: http://www.redpill-linpro.com/

Date: Fri, 3 Sep 2010 09:41:17 +0200
Subject: Re: [GENERAL] Compiling extension C with MingW in windows, Error...
From: magnus@hagander.net
To: listas_quijada@hotmail.com
CC: pgsql-general@postgresql.org

On Fri, Sep 3, 2010 at 5:31 AM, Edwin Quijada
<listas_quijada@hotmail.com> wrote:

Hi, I am tryng to compile a C extension in windows using Minigw but always I
get the same error

C:\Program Files\PostgreSQL\8.3\share\exte_c>C:\mingw\bin\gcc -shared -o
pg2.dll
pg2.o
pg2.o:pg2.c:(.text+0x86): undefined reference to
`_imp__CurrentMemoryContext'
pg2.o:pg2.c:(.text+0x92): undefined reference to `MemoryContextAlloc'
collect2: ld returned 1 exit status

This error is just when it links.

You need to link against postgres.exe to get access to these symbols.
I don't recall if the mingw linker allows you to just specify the EXE
file these days, but I think it does. If not, you'll need to create an
import library from the EXE and link to that (the binary distribution
only ships with import libraries for MSVC, but mingw can't use
standard windows import libraries, so you need to create your own
there)

Magnus how can I linking against postgres.exe I mean the gcc line. I did others function and worked fine

This is the function that I did and worked, with this code I did a foo.dll and added this to postgresql.

#include "postgres.h"
#include <string.h>
#include "fmgr.h"

#ifdef PG_MODULE_MAGIC
PG_MODULE_MAGIC;
#endif

/* by value */

PG_FUNCTION_INFO_V1(add_one);

Datum add_one(PG_FUNCTION_ARGS)
{
int32 arg = PG_GETARG_INT32(0);

PG_RETURN_INT32(arg + 1);
}

*-------------------------------------------------------*
*-Edwin
Quijada
*-Developer DataBase
*-JQ Microsistemas

*-Soporte PostgreSQL

*-www.jqmicrosistemas.com
*-809-849-8087
*-------------------------------------------------------*

On Fri, Sep 3, 2010 at 18:23, Edwin Quijada <listas_quijada@hotmail.com> wrote:

Date: Fri, 3 Sep 2010 09:41:17 +0200
Subject: Re: [GENERAL] Compiling extension C with MingW in windows,
Error...
From: magnus@hagander.net
To: listas_quijada@hotmail.com
CC: pgsql-general@postgresql.org

On Fri, Sep 3, 2010 at 5:31 AM, Edwin Quijada
<listas_quijada@hotmail.com> wrote:

Hi, I am tryng to compile a C extension in windows using Minigw but
always I
get the same error

C:\Program Files\PostgreSQL\8.3\share\exte_c>C:\mingw\bin\gcc -shared -o
pg2.dll
 pg2.o
pg2.o:pg2.c:(.text+0x86): undefined reference to
`_imp__CurrentMemoryContext'
pg2.o:pg2.c:(.text+0x92): undefined reference to `MemoryContextAlloc'
collect2: ld returned 1 exit status

This error is just when it links.

You need to link against postgres.exe to get access to these symbols.
I don't recall if the mingw linker allows you to just specify the EXE
file these days, but I think it does. If not, you'll need to create an
import library from the EXE and link to that (the binary distribution
only ships with import libraries for MSVC, but mingw can't use
standard windows import libraries, so you need to create your own
there)

Magnus how can I linking against postgres.exe I mean the gcc line. I did
others function and worked fine

Sorry, I don't know this. I don't use mingw myself anymore. But it
should work in the same way as you link against any other third-party
DLLs with it - DLLs and EXEs are actually the same thing, just with
different names...

--
 Magnus Hagander
 Me: http://www.hagander.net/
 Work: http://www.redpill-linpro.com/