organize the PostgreSQL database connection parameters using libpq?

Question

I'm trying to figure out the correct way to pass database connection parameters to this libpq connection control function.

PQconnectdbParams

PGconn *PQconnectdbParams(const char * const *keywords,
    const char * const *values, int expand_dbname);  

Answer 1

From the documentation:

This function opens a new database connection using the parameters taken from two NULL-terminated arrays. The first, keywords, is defined as an array of strings, each one being a key word. The second, values, gives the value for each key word.

I have never used this function in practice (as PQconnectdb() seems simpler), but this example should work I think:

char *keywords[] = {"hostaddr", "port", "dbname", 0};
char *values[] = {"127.0.0.1", "5432", "testdb", 0};

conn = PQconnectdbParams((const char **)keywords, (const char **)values, 0);