_c.sql.query.partial

// compile with
// g++ libpq_example.c -o libpq_example.exe  -I pgsql\include -L dev\pgsql\lib
// -std=c++17  -lpthread -lpq
#include <libpq-fe.h>
#include <stdio.h>
#include <stdlib.h>

void do_exit(PGconn *conn) {
  PQfinish(conn);
  exit(1);
}

int main() {
  PGconn *conn = PQconnectdb(
      "host=localhost user=admin password=quest port=8812 dbname=testdb");
  if (PQstatus(conn) == CONNECTION_BAD) {
    fprintf(stderr, "Connection to database failed: %s\n",
            PQerrorMessage(conn));
    do_exit(conn);
  }
  PGresult *res = PQexec(conn, "SELECT x FROM long_sequence(5);");
  if (PQresultStatus(res) != PGRES_TUPLES_OK) {
    printf("No data retrieved\n");
    PQclear(res);
    do_exit(conn);
  }
  int rows = PQntuples(res);
  for (int i = 0; i < rows; i++) {
    printf("%s\n", PQgetvalue(res, i, 0));
  }
  PQclear(res);
  PQfinish(conn);
  return 0;
}