Example 4: Setting up an event that triggers the copy

This program demonstrates how to use asyncmsg_connect_attach() to set the event that's used to trigger copying by the receiver.

#include <stdio.h>
#include <process.h>
#include <unistd.h>
#include <string.h>
#include <sys/asyncmsg.h>

char *msg = "AsyncMsg Passing";

int callback(int err, void *cmsg, unsigned handle)
{
    printf("Callback: err = %d, msg = %p (%p), handle = %d\n",
           err, cmsg, msg, handle);
    return 0;
}

/*
 * Simple test. Create a channel, connect to it, put a message,
 * get them, done
 */
int main()
{
    int chid, coid, pchid;
    struct sigevent gev;
    struct _pulse pulse;
    struct _asyncmsg_connection_attr aca;
    struct _asyncmsg_get_header *agh, *agh1;

    /* 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(0, 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 = 1;
        aca.call_back = callback;

        if ((coid = asyncmsg_connect_attach(0, 0, chid, 0, 0, &aca)) == -1)
        {
            perror("connect_attach");
            return -1;
        }

        if ((asyncmsg_put(coid, msg, strlen(msg) + 1, 0, 0)) == -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;
}