#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <postgresql/libpq-fe.h>
#include <postgresql/9.5/server/postgres.h>

struct DbConfig {
  char host[30];
  char dbName[30];
  char userName[30];
  char password[30];
}

int main(int argc, char *argv[]) {
  struct DbConfig dbConfig;
  dbConfig.host     = "host";
  dbConfig.dbName   = "db_name";
  dbConfig.userName = "user_name";
  dbConfig.password = "password";

  PGconn *con;
  PGresult *res;

  con = PQsetdb(
    dbConfig.host,
    "",
    NULL,
    NULL,
    dbConfig.userName,
    dbConfig.password);
  if (PQstatus(con) == CONNECTION_BAD) exit(1);
  res = PQexec(con, "select 1");

  PQclear(res);
  return 0;
}