Hello I am having problems linking to the libpq++ libraries. I tried compiling the the program below that I found in
thearchive just like
it said
c++ test3.cpp -o test3 -lpq -lpq++
But I get messages like the following:
/usr/lib/qt/include/qarray.h(.gnu.linkonce.t__tf10PgDatabase+0xd): undefined
reference to 'PgConnection type_info function
Before I had to specify the location of the libpq++.h file until I used
the I switch or else it would say the file was not found.
c++ test3.cpp -o test3 -I/usr/lib/pgsql/include -lpq -lpq++
So I have a couple of questions
1. How do I fix the linking error?
2. When I set the -lpq and -lpq++ I know it is suppose to be including those
libraries but do I need to tell the system where those libraries are? How does
it know?
Please HELP!! :-)
Thanks,
Mike
mfre@telusplanet.net
*************************************************************************************************************************
/* test3.h
joris esch 3.10.1998
*/
#include <libpq++.h>
//#include "/usr/lib/pgsql/include/libpq++.h"
#include <iostream>
//typedef int Error;
/* test3.cpp
joris esch 3.10.1998
*/
// compile with:
// c++ test3.cpp -o test3 -lpq -lpq++
#include "test3.h"
void main()
{ bool verbose = true; char* dbname= "template1";
/* make a connection to the database */ if (verbose) { cout << "Trying to connect to db " << dbname << '\n';; //
<<" on host " << pghost; } ; // PgDatabase inherits from PgConnection PgDatabase *conn=new PgDatabase(dbname);
// give error messages if conn is not ok
if (conn->Status()!=0){ cerr << "Connection status: " << conn->Status() <<'\n'; cerr << "Connection failed." <<
'\n'; cerr << "Database name: " << conn->DBName() << '\n'; cerr << conn->ErrorMessage() << '\n'; //end execution
here...or use exception handling...cfr. ch8 exit(1); //Stroustrup page 116 0== okidoki, 1!=okidoki //throw
"Connectionfailed"; }; if (verbose) {cout << "Connection succeeded.\n";}; cout << "You are currently connected to
db:" << conn->DBName() << '\n'; //cout << "Let's do a query"; //see if i can do query... if
(conn->ExecTuplesOk("DECLAREmycursor BINARY CURSOR FOR select * from pg_database")){// 1 means Ok int
no_t=conn->Tuples(); int no_f=conn->Fields(); if (verbose) { cout << "The number of tuples in the query: " <<
conn->Tuples()<< '\n'; cout << "The number of fields in the query: " << conn->Fields() << '\n'; } cout << "The
queryresults: \n"; for(int i=0;i < no_t; i++){ for(int j=0;j < no_f; j++){ cout << conn->GetValue(i,j) <<
'\t'; //cout << conn->GetValue(i,j) << '\n'; } cout << '\n'; } } else{ cout << "Execution of query
failed\n";//conn}
//conn->Exec("DECLARE mycursor BINARY CURSOR FOR select * from test"); //return 0;
}
************
