Connecting - Need Help !

I am trying my first attempt to write code which will conect to a test
database I have created.

The code I used is shown below:

void ConnectDatabase()
{
char *pghost;
char *pgport;
char *pgoptions;
char *pgtty;
char *dbName;

PGconn *conn;
PGresult *res;

pghost = NULL;
pgport = NULL;
pgoptions = NULL;
dbName = "linlog";

conn = PQsetdb(pghost,pgport,pgoptions,pgtty,dbName);
}

When I compile and make I get the following error:

linlog.o(.text+0x177): In function `ConnectDatabase()':
/home/pmoscatt/C++/linlog/linlog/linlog.cpp:30: undefined reference to
`PQsetdbLogin'
collect2: ld returned 1 exit status
gmake[2]: *** [linlog] Error 1
gmake[2]: Leaving directory `/home/pmoscatt/C++/linlog/linlog'
gmake[1]: Leaving directory `/home/pmoscatt/C++/linlog'
gmake[1]: *** [all-recursive] Error 1
gmake: *** [all-recursive-am] Error 2
*** failed ***

What have I done wrong here ??

Pete