Problem calling C function in PostgreSQL

Hi,

I am new to PostgreSQL and could anyone please suggest me any windows based C compiler which will successfully create a dll on windows and which can be callable by PostgreSQL.

I am facing a problem with the below code compiled and created dll in MSVC 2005.

_______________________________________________________________________

Here is my code:

#define _USE_32BIT_TIME_T
#include "postgres.h"
#include "fmgr.h"

//#ifdef PG_MODULE_MAGIC
PG_MODULE_MAGIC;
//#endif

PG_FUNCTION_INFO_V1(add_one);
Datum add_one(PG_FUNCTION_ARGS)
{
int32 arg = PG_GETARG_INT32(0);

PG_RETURN_INT32(arg + 1);
}

______________________________________________________________

But when I am calling this function from POstgreSQL the below error is thrown.
____________________________________________________________________________
CREATE OR REPLACE FUNCTION add_test(iparam int) RETURNS int AS '$libdir/add', 'add_one' LANGUAGE C;

ERROR: could not find function "add_one" in file "C:/Program Files/PostgreSQL/8.3/lib/add.dll"
____________________________________________________________________________

It would be kind if any help!

Thanks and regards
AB