From: "Erny" <aerd@mx3.redestb.es>
References: <Pine.SGI.4.10.10104191831150.839-100000@micro.iisc.ernet.in>
Subject: RE: Postgres problem
Date: Mon, 21 May 2001 22:41:30 +0200
Lines: 43
Message-ID: <3b0980f4@news>
To: pgsql-interfaces@postgresql.org

> Hello:
Hi,

>
> I am having problem interfacing the postgres database with the
> frontend(libpq),i.e using C.Database runs fine.
>
>  PROBLEMS ARE:
>             1)When compiling the C-program given in the
>              example for connecting the database to the
>              frontend using
>        $gcc -I /home/guest/pgsql/include test.c
>
>        output:
>             /tmp/ccwWFbHo.o:In function 'exit_nicely':
>             /tmp/ccwWFbHo.o(.text+0x8):undefined referance to 'PQfinish'
>
>             /tmp/ccwWFbHo.o:In function 'main':
>             /tmp/ccwWFbHo.o(.text+0x66):undefined referance to
> 'PQsetdblogin'
>
>             /tmp/ccwWFbHo.o(.text+0x66):undefined referance to 'PQstatus'

I had the same problem. You have to include -lq on the command line.
Futhermore, I had to put it on the end of the line, because the compiler
collects unknown symbols first and then resolves it with the -l library
switch. So I made a little Makefile like this one:

#Little Makefile for making whatever source file directly to an executable.
override CFLAGS += -I/usr/include/postgresql

% : %.c
        $(CC) $(CFLAGS) $(LDFLAGS) -o $@ $< -lpq

% : %.c++
        g++ $(CFLAGS) $(LDFLAGS) -o $@ $< -lpq++

#end

Erny