1 files changed, 163 insertions, 0 deletions
diff --git a/src/test/examples/testlibpq4.c b/src/test/examples/testlibpq4.c
new file mode 100644
index 0000000..da44430
--- /dev/null
+++ b/src/test/examples/testlibpq4.c
@@ -0,0 +1,163 @@
+/*
+ * src/test/examples/testlibpq4.c
+ *
+ *
+ * testlibpq4.c
+ *		this test program shows to use LIBPQ to make multiple backend
+ * connections
+ *
+ */
+#include <stdio.h>
+#include <stdlib.h>
+#include "libpq-fe.h"
+
+static void
+exit_nicely(PGconn *conn1, PGconn *conn2)
+{
+	if (conn1)
+		PQfinish(conn1);
+	if (conn2)
+		PQfinish(conn2);
+	exit(1);
+}
+
+static void
+check_prepare_conn(PGconn *conn, const char *dbName)
+{
+	PGresult   *res;
+
+	/* check to see that the backend connection was successfully made */
+	if (PQstatus(conn) != CONNECTION_OK)
+	{
+		fprintf(stderr, "%s", PQerrorMessage(conn));
+		exit(1);
+	}
+
+	/* Set always-secure search path, so malicious users can't take control. */
+	res = PQexec(conn,
+				 "SELECT pg_catalog.set_config('search_path', '', false)");
+	if (PQresultStatus(res) != PGRES_TUPLES_OK)
+	{
+		fprintf(stderr, "SET failed: %s", PQerrorMessage(conn));
+		PQclear(res);
+		exit(1);
+	}
+	PQclear(res);
+}
+
+int
+main(int argc, char **argv)
+{
+	char	   *pghost,
+			   *pgport,
+			   *pgoptions;
+	char	   *dbName1,
+			   *dbName2;
+	char	   *tblName;
+	int			nFields;
+	int			i,
+				j;
+
+	PGconn	   *conn1,
+			   *conn2;
+
+	/*
+	 * PGresult   *res1, *res2;
+	 */
+	PGresult   *res1;
+
+	if (argc != 4)
+	{
+		fprintf(stderr, "usage: %s tableName dbName1 dbName2\n", argv[0]);
+		fprintf(stderr, "      compares two tables in two databases\n");
+		exit(1);
+	}
+	tblName = argv[1];
+	dbName1 = argv[2];
+	dbName2 = argv[3];
+
+
+	/*
+	 * begin, by setting the parameters for a backend connection if the
+	 * parameters are null, then the system will try to use reasonable
+	 * defaults by looking up environment variables or, failing that, using
+	 * hardwired constants
+	 */
+	pghost = NULL;				/* host name of the backend */
+	pgport = NULL;				/* port of the backend */
+	pgoptions = NULL;			/* special options to start up the backend
+								 * server */
+
+	/* make a connection to the database */
+	conn1 = PQsetdb(pghost, pgport, pgoptions, NULL, dbName1);
+	check_prepare_conn(conn1, dbName1);
+
+	conn2 = PQsetdb(pghost, pgport, pgoptions, NULL, dbName2);
+	check_prepare_conn(conn2, dbName2);
+
+	/* start a transaction block */
+	res1 = PQexec(conn1, "BEGIN");
+	if (PQresultStatus(res1) != PGRES_COMMAND_OK)
+	{
+		fprintf(stderr, "BEGIN command failed\n");
+		PQclear(res1);
+		exit_nicely(conn1, conn2);
+	}
+
+	/*
+	 * make sure to PQclear() a PGresult whenever it is no longer needed to
+	 * avoid memory leaks
+	 */
+	PQclear(res1);
+
+	/*
+	 * fetch instances from the pg_database, the system catalog of databases
+	 */
+	res1 = PQexec(conn1, "DECLARE myportal CURSOR FOR select * from pg_database");
+	if (PQresultStatus(res1) != PGRES_COMMAND_OK)
+	{
+		fprintf(stderr, "DECLARE CURSOR command failed\n");
+		PQclear(res1);
+		exit_nicely(conn1, conn2);
+	}
+	PQclear(res1);
+
+	res1 = PQexec(conn1, "FETCH ALL in myportal");
+	if (PQresultStatus(res1) != PGRES_TUPLES_OK)
+	{
+		fprintf(stderr, "FETCH ALL command didn't return tuples properly\n");
+		PQclear(res1);
+		exit_nicely(conn1, conn2);
+	}
+
+	/* first, print out the attribute names */
+	nFields = PQnfields(res1);
+	for (i = 0; i < nFields; i++)
+		printf("%-15s", PQfname(res1, i));
+	printf("\n\n");
+
+	/* next, print out the instances */
+	for (i = 0; i < PQntuples(res1); i++)
+	{
+		for (j = 0; j < nFields; j++)
+			printf("%-15s", PQgetvalue(res1, i, j));
+		printf("\n");
+	}
+
+	PQclear(res1);
+
+	/* close the portal */
+	res1 = PQexec(conn1, "CLOSE myportal");
+	PQclear(res1);
+
+	/* end the transaction */
+	res1 = PQexec(conn1, "END");
+	PQclear(res1);
+
+	/* close the connections to the database and cleanup */
+	PQfinish(conn1);
+	PQfinish(conn2);
+
+/*	 fclose(debug); */
+	return 0;
+}