About the authentication when using PQconnectdb() to connect pq server in windows

Question

I have installed postgresql9.2.4 in my win7 laptop and have wrote a simple program to test the connection in my vs2008.The code is here:

#include "stdafx.h"
#include <windows.h>
#include "libpq-fe.h"


int _tmain(int argc, _TCHAR* argv[])
{
    const char *conninfo;
    PGconn     *conn;

    conninfo = "password = password";

    conn = PQconnectdb(conninfo);

    if (PQstatus(conn) != CONNECTION_OK)
    {
        printf("Connection to database failed: %s",
                PQerrorMessage(conn));
    }

    system("pause");
    return 0;
}

It showed an error that about authentication fail after ran it. I know it was the fault about password, it shoulded be md5 encrypted.So I searched in google.There almost no issue about this problem.I found a head file named "md5.h" in libpq folder and has a function named "pg_md5_hash", I tried it and came with many link error. Can anyone give me some suggestions? Thanks.

Answer 1

You don't have to encrypt password by yourself. Libpq is choosing authentication method depending on pg_hba.conf configuration.

Your conninfo is far from proper. You provided password, but you missed at least database and user name.