Function udp_write

libavformat/udp.c:1044–1092

}

static int udp_write(URLContext *h, const uint8_t *buf, int size)
{
    UDPContext *s = h->priv_data;
    int ret;

#if HAVE_PTHREAD_CANCEL
    if (s->tx_fifo) {
        uint8_t tmp[4];

        pthread_mutex_lock(&s->mutex);

        /*
          Return error if last tx failed.
          Here we can't know on which packet error was, but it needs to know that error exists.
        */
        if (s->circular_buffer_error<0) {
            int err = s->circular_buffer_error;
            pthread_mutex_unlock(&s->mutex);
            return err;
        }

        if (av_fifo_can_write(s->tx_fifo) < size + 4) {
            /* What about a partial packet tx ? */
            pthread_mutex_unlock(&s->mutex);
            return AVERROR(ENOMEM);
        }
        AV_WL32(tmp, size);
        av_fifo_write(s->tx_fifo, tmp, 4); /* size of packet */
        av_fifo_write(s->tx_fifo, buf, size); /* the data */
        pthread_cond_signal(&s->cond);
        pthread_mutex_unlock(&s->mutex);
        return size;
    }
#endif
    if (!(h->flags & AVIO_FLAG_NONBLOCK)) {
        ret = ff_network_wait_fd(s->udp_fd, 1);
        if (ret < 0)
            return ret;
    }

    if (!s->is_connected) {
        ret = sendto (s->udp_fd, buf, size, 0,
                      (struct sockaddr *) &s->dest_addr,
                      s->dest_addr_len);
    } else
        ret = send(s->udp_fd, buf, size, 0);

    return ret < 0 ? ff_neterrno() : ret;
}

static int udp_close(URLContext *h)
{