Example 1: Sending one message

This is the most simple example; it demonstrates the sending and receiving of one message. The trigger number, which defines the number of messages the sender wants to send at once, is set to 1.

#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 it, done.
 */
int main()
{
    int chid, coid;
    struct _asyncmsg_connection_attr aca;
    struct _asyncmsg_get_header *agh, *agh1;

    if ((chid = asyncmsg_channel_create(0, 0666, 2048, 5, NULL, 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;

        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, 1234, callback)) 
            == -1)
        {
            perror("put");
            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;
}