diff options
Diffstat (limited to 'lib/ose/doc/src/ose_signals_chapter.xml')
| -rw-r--r-- | lib/ose/doc/src/ose_signals_chapter.xml | 23 |
1 files changed, 21 insertions, 2 deletions
diff --git a/lib/ose/doc/src/ose_signals_chapter.xml b/lib/ose/doc/src/ose_signals_chapter.xml index 85849e1a39..c8d98f4099 100644 --- a/lib/ose/doc/src/ose_signals_chapter.xml +++ b/lib/ose/doc/src/ose_signals_chapter.xml @@ -77,7 +77,12 @@ in this case the port id that we got in the <seealso marker="erts:driver_entry#start">start</seealso> callback is used. The third argument is a function pointer to a function that can - be used to figure out the id from a given signal. There is a complete + be used to figure out the id from a given signal. The fourth argument can + point to any additional data you might want to associate with the event. + There is a complete. You can examine the data contained in the event with + <seealso marker="ose_erl_driver#erl_drv_ose_event_fetch">erl_drv_ose_event_fetch</seealso> + , eg: + <code>erl_drv_ose_event_fetch(event, &signal, &port, (void **)&extra);</code> example of what this could look like in <seealso marker="#example">the next section</seealso>. <note>It is very important to issue the driver_select call before @@ -132,8 +137,12 @@ static ErlDrvSSizeT control(ErlDrvData driver_data, unsigned int cmd, char **rbuf, ErlDrvSizeT rlen) { ErlDrvPort port = (ErlDrvPort)driver_data; + /* An example of extra data to associate with the event */ + char *extra_data = driver_alloc(80); + snprintf("extra_data, "Event, sig_no: 1234, and port: %d", port); + /* Create a new event to select on */ - ErlDrvOseEvent evt = erl_drv_ose_event_alloc(1234,port,resolver); + ErlDrvOseEvent evt = erl_drv_ose_event_alloc(1234,port,resolver, extra_data); /* Make sure to do the select call _BEFORE_ the signal arrives. The signal might get lost if the hunt call is done before the @@ -147,11 +156,16 @@ static ErlDrvSSizeT control(ErlDrvData driver_data, unsigned int cmd, } static void ready_input(ErlDrvData driver_data, ErlDrvEvent evt) { + char *extra_data; /* Get the first signal payload from the event */ union SIGNAL *sig = erl_drv_ose_get_signal(evt); ErlDrvPort port = (ErlDrvPort)driver_data; while (sig != NULL) { if (sig->signo == 1234) { + /* Print out the string we added as the extra parameter */ + erl_drv_ose_event_fetch(evt, NULL, NULL, (void **)&extra_data); + printf("We've received: %s\n", extra_data); + /* If it is our signal we send a message with the sender of the signal to the controlling erlang process */ ErlDrvTermData reply[] = { ERL_DRV_UINT, (ErlDrvUInt)sender(&sig) }; @@ -172,6 +186,11 @@ static void ready_input(ErlDrvData driver_data, ErlDrvEvent evt) { static void stop_select(ErlDrvEvent event, void *reserved) { + /* Free the extra_data */ + erl_drv_ose_event_fetch(evt, NULL, NULL, (void **)&extra_data); + driver_free(extra_data); + + /* Free the event itself */ erl_drv_ose_event_free(event); } |