mirror of
https://github.com/postgres/postgres.git
synced 2025-06-14 18:42:34 +03:00
ce7b35e7e8
<sys/select.h> is required by POSIX.1-2001 to get the prototype of select(2), but nearly no systems enforce that because older standards let you get away with including some other headers. Recent OpenBSD hacking has removed that frail touch of friendliness, however, which broke some compiles; fix all the way back to 9.1 by adding the required standard. Only vacuumdb.c was reported to fail, but it seems easier to fix the whole lot in a fell swoop. Per bug #14334 by Sean Farrell.
142 lines
3.0 KiB
C
142 lines
3.0 KiB
C
/*
|
|
* src/test/examples/testlibpq2.c
|
|
*
|
|
*
|
|
* testlibpq2.c
|
|
* Test of the asynchronous notification interface
|
|
*
|
|
* Start this program, then from psql in another window do
|
|
* NOTIFY TBL2;
|
|
* Repeat four times to get this program to exit.
|
|
*
|
|
* Or, if you want to get fancy, try this:
|
|
* populate a database with the following commands
|
|
* (provided in src/test/examples/testlibpq2.sql):
|
|
*
|
|
* CREATE TABLE TBL1 (i int4);
|
|
*
|
|
* CREATE TABLE TBL2 (i int4);
|
|
*
|
|
* CREATE RULE r1 AS ON INSERT TO TBL1 DO
|
|
* (INSERT INTO TBL2 VALUES (new.i); NOTIFY TBL2);
|
|
*
|
|
* and do this four times:
|
|
*
|
|
* INSERT INTO TBL1 VALUES (10);
|
|
*/
|
|
|
|
#ifdef WIN32
|
|
#include <windows.h>
|
|
#endif
|
|
#include <stdio.h>
|
|
#include <stdlib.h>
|
|
#include <string.h>
|
|
#include <errno.h>
|
|
#include <sys/time.h>
|
|
#include <sys/types.h>
|
|
#ifdef HAVE_SYS_SELECT_H
|
|
#include <sys/select.h>
|
|
#endif
|
|
|
|
#include "libpq-fe.h"
|
|
|
|
static void
|
|
exit_nicely(PGconn *conn)
|
|
{
|
|
PQfinish(conn);
|
|
exit(1);
|
|
}
|
|
|
|
int
|
|
main(int argc, char **argv)
|
|
{
|
|
const char *conninfo;
|
|
PGconn *conn;
|
|
PGresult *res;
|
|
PGnotify *notify;
|
|
int nnotifies;
|
|
|
|
/*
|
|
* If the user supplies a parameter on the command line, use it as the
|
|
* conninfo string; otherwise default to setting dbname=postgres and using
|
|
* environment variables or defaults for all other connection parameters.
|
|
*/
|
|
if (argc > 1)
|
|
conninfo = argv[1];
|
|
else
|
|
conninfo = "dbname = postgres";
|
|
|
|
/* Make a connection to the database */
|
|
conn = PQconnectdb(conninfo);
|
|
|
|
/* Check to see that the backend connection was successfully made */
|
|
if (PQstatus(conn) != CONNECTION_OK)
|
|
{
|
|
fprintf(stderr, "Connection to database failed: %s",
|
|
PQerrorMessage(conn));
|
|
exit_nicely(conn);
|
|
}
|
|
|
|
/*
|
|
* Issue LISTEN command to enable notifications from the rule's NOTIFY.
|
|
*/
|
|
res = PQexec(conn, "LISTEN TBL2");
|
|
if (PQresultStatus(res) != PGRES_COMMAND_OK)
|
|
{
|
|
fprintf(stderr, "LISTEN command failed: %s", PQerrorMessage(conn));
|
|
PQclear(res);
|
|
exit_nicely(conn);
|
|
}
|
|
|
|
/*
|
|
* should PQclear PGresult whenever it is no longer needed to avoid memory
|
|
* leaks
|
|
*/
|
|
PQclear(res);
|
|
|
|
/* Quit after four notifies are received. */
|
|
nnotifies = 0;
|
|
while (nnotifies < 4)
|
|
{
|
|
/*
|
|
* Sleep until something happens on the connection. We use select(2)
|
|
* to wait for input, but you could also use poll() or similar
|
|
* facilities.
|
|
*/
|
|
int sock;
|
|
fd_set input_mask;
|
|
|
|
sock = PQsocket(conn);
|
|
|
|
if (sock < 0)
|
|
break; /* shouldn't happen */
|
|
|
|
FD_ZERO(&input_mask);
|
|
FD_SET(sock, &input_mask);
|
|
|
|
if (select(sock + 1, &input_mask, NULL, NULL, NULL) < 0)
|
|
{
|
|
fprintf(stderr, "select() failed: %s\n", strerror(errno));
|
|
exit_nicely(conn);
|
|
}
|
|
|
|
/* Now check for input */
|
|
PQconsumeInput(conn);
|
|
while ((notify = PQnotifies(conn)) != NULL)
|
|
{
|
|
fprintf(stderr,
|
|
"ASYNC NOTIFY of '%s' received from backend PID %d\n",
|
|
notify->relname, notify->be_pid);
|
|
PQfreemem(notify);
|
|
nnotifies++;
|
|
}
|
|
}
|
|
|
|
fprintf(stderr, "Done.\n");
|
|
|
|
/* close the connection to the database and cleanup */
|
|
PQfinish(conn);
|
|
|
|
return 0;
|
|
}
|