In this example, you use time to trigger the copying by the receiver. Here, a timer is set for a certain period of time (for example, 2 seconds). After the timer expires, the receiver gets the notification and starts copying the messages.
#include <stdio.h> #include <process.h> #include <unistd.h> #include <string.h> #include <sys/asyncmsg.h> int callback(int err, void *cmsg, unsigned handle) { printf("Callback: err = %d, msg = %p, handle = %d\n", err, cmsg, handle); return 0; } /* * Set the get trigger to 2 seconds, put up 4 messages, see we could get a * notification for get after 2 seconds. */ int main() { int chid, coid, pchid, i; struct sigevent gev; struct _pulse pulse; struct _asyncmsg_connection_attr aca; struct _asyncmsg_get_header *agh, *agh1; char msg[4][80]; /* prepare the event */ if ((pchid = ChannelCreate(0)) == -1) { perror("ChannelCreate"); return -1; } if ((gev.sigev_coid = ConnectAttach(0, 0, pchid, _NTO_SIDE_CHANNEL, 0)) == -1) { perror("ConnectAttach"); return -1; } gev.sigev_notify = SIGEV_PULSE; gev.sigev_priority = SIGEV_PULSE_PRIO_INHERIT; /* async channel */ if ((chid = asyncmsg_channel_create(_NTO_CHF_SENDER_LEN, 0666, 2048, 5, &gev, NULL)) == -1) { perror("channel_create"); return -1; } memset(&aca, 0, sizeof(aca)); aca.buffer_size = 2048; aca.max_num_buffer = 5; aca.trigger_num_msg = 0; aca.trigger_time.nsec = 2000000000L; aca.trigger_time.interval_nsec = 0; aca.call_back = callback; if ((coid = asyncmsg_connect_attach(0, 0, chid, 0, 0, &aca)) == -1) { perror("connect_attach"); return -1; } /* put up 4 messages */ for (i = 0; i < 4; i++) { sprintf(msg[i], "Async Message Passing (msgid %d)\n", i); if ((asyncmsg_put(coid, msg[i], strlen(msg[i]) + 1, 1234, callback)) == -1) { perror("put"); return -1; } } /* waiting for the event */ if (MsgReceivePulse(pchid, &pulse, sizeof(pulse), NULL) == -1) { perror("MsgReceivePulse"); return -1; } if ((agh = asyncmsg_get(chid)) == NULL) { perror("get"); return -1; } printf("Got message(s): \n\n"); while ((agh1 = agh)) { agh = agh1->next; printf("from process: %d (%d)\n", agh1->info.pid, getpid()); printf("msglen: %d (%d)\n", agh1->info.msglen, strlen(*msg) + 1); printf("srclen: %d\n", agh1->info.srcmsglen); printf("err: %d\n", agh1->err); printf("parts: %d\n", agh1->parts); printf("msg: %s\n\n", (char *)agh1->iov->iov_base); asyncmsg_free(agh1); } /* give the callback a chance to run */ sleep(1); if (asyncmsg_connect_detach(coid) == -1) { perror("connect_detach"); return -1; } if (asyncmsg_channel_destroy(chid) == -1) { perror("channel_detach"); return -1; } return 0; }