/*
 * gcc multiple_hosts_test.c -lpq -I/home/postgres/work/pgsql10/include -L/home/postgres/work/pgsql10/lib
 * if target_session_attrs=read-write,  "another command is already in progress" is occured
 */

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#ifdef WIN32
#include <winsock2.h>
#endif
#include "libpq-fe.h"

int main( int argc, char *argv[])
{
	int i=0,rtn;
	PGconn *conn;
	PGresult *r;
	const char *keywords[5];
	const char *values[5];

	/*
	** Connect to postgres
	*/
	keywords[0] = "dbname";
	values[0] = "postgres";
	keywords[1] = "port";
	values[1] = (char *)getenv("PGPORT"); /* export PGPORT=5432,5433 */
	keywords[1] = "host";
	values[1] = (char *)getenv("PGHOST"); /* export PGHOST=localhost,localhost */
	keywords[2] = "target_session_attrs";
	values[2] = "read-write";
	keywords[3] = NULL;
	values[3] = NULL;
	conn = PQconnectdbParams((const char * const*)&keywords, (const char * const*)&values, 1);
	if (PQstatus(conn) != CONNECTION_OK)
	{
		printf("Connection to database failed: %s \n",PQerrorMessage(conn));
		goto ERR;
	}
	printf("host=%s,port=%s\n",PQhost(conn),PQport(conn));

	/*
	** Asynchronous statement
	*/
	printf("-- SHOW transaction_read_only --\n");
	rtn = PQsendQuery(conn, "SHOW transaction_read_only");
	if (rtn != 1)
	{
		printf( "SHOW command failed: %s", PQerrorMessage(conn));
		goto ERR;
	}
	r = PQgetResult(conn);
	printf("SHOW transaction_read_only:%s\n",PQgetvalue(r, 0, 0));
	r = PQgetResult(conn);
	PQclear(r);

	/*
	** Disconnect
	*/
	PQfinish(conn);
	printf("Success!\n");

	return(0);

ERR:
	PQfinish(conn);
	printf("Failed!\n");

	return(1);
}