[lug] C extensions of PostgreSQL

[rm at fabula.de]

On Wed, Aug 06, 2003 at 02:52:14PM -0600, B Giles wrote:
> >I just want to know what lib to link...the sample code I have is fine, it 
> >is coded and complete...what I need is for a lib that implements 
> >functionality for palloc (those symbols missing are because palloc 
> >references them).
> 
> I keep thinking that you're missing some registration functions, but maybe 
> that's only with user-defined types or people who need to initialize an 
> external library.  E.g., I had to initialize the OpenSSL library and 
> configure it to use palloc instead of the default memory allocation 
> routines.

Nope, no need to do that for a function. That pretty much get's incorporated
into the backend by dlopening the (.so) file and finding the corresponding
c function by name.

AFAIK there is no special library one has to link against -- pmalloc
is provided by the host application (so including the appropriate 
headers should be enough). Of course the compiler/linker has to know that
it is supposed to build  shared code (-fPIC and -shared should do that).

# -----x snip x---------------------------------------------------------

PREFIX=/usr/local

# use pg_config to query installation locations
PGCONFIG=pg_config

CC = gcc
CFLAGS = -I `$(PGCONFIG) --includedir` \
         -I `$(PGCONFIG) --includedir-server` \
         -fpic -shared

LIBS = -L `$(PGCONFIG) --libdir`
WARNINGS = -Wall -Wmissing-prototypes

INSTDIR = `$(PGCONFIG) --pkglibdir`

SRC=facts.c

install: dso
        install -D -o postgres facts.so $(INSTDIR)/facts.so

dso: facts.so

facts.so: facts.c facts.h Makefile
        $(CC) $(WARNINGS) $(CFLAGS) $(LIBS) -o facts.so $(SRC)

#-----------x snip x-------------------------------------------


 hth Ralf Mattes