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XS_GETMSGOPT(3)              Crossroads I/O Manual             XS_GETMSGOPT(3)

NAME
       xs_getmsgopt - retrieve message option

SYNOPSIS
       int xs_getmsgopt (xs_msg_t *message, int option_name, void
       *option_value, size_t *option_len);

DESCRIPTION
       The xs_getmsgopt() function shall retrieve the value for the option
       specified by the option_name argument for the message pointed to by the
       message argument, and store it in the buffer pointed to by the
       option_value argument. The option_len argument is the size in bytes of
       the buffer pointed to by option_value; upon successful completion
       xs_getsockopt() shall modify the option_len argument to indicate the
       actual size of the option value stored in the buffer.

       The following options can be retrieved with the xs_getmsgopt()
       function:

       XS_MORE
           Indicates that there are more message parts to follow after the
           message. The type of this option is int. 0 means that this is the
           last message part of a multipart message. 1 means that more message
           parts will follow.

RETURN VALUE
       The xs_getmsgopt() function shall return zero if successful. Otherwise
       it shall return -1 and set errno to one of the values defined below.

ERRORS
       EINVAL
           The requested option option_name is unknown, or the requested
           option_size or option_value is invalid, or the size of the buffer
           pointed to by option_value, as specified by option_len, is
           insufficient for storing the option value.

EXAMPLE
       Receiving a multi-part message.

           xs_msg_t part;
           int more;
           size_t more_size = sizeof (more);
           while (true) {
               /* Create an empty message to hold the message part */
               int rc = xs_msg_init (&part);
               assert (rc == 0);
               /* Block until a message is available to be received from socket */
               rc = xs_recvmsg (socket, &part, 0);
               assert (rc != -1);
               rc = getmsgopt (&part, XS_MORE, &more, &more_size);
               assert (rc == 0);
               if (more) {
                 fprintf (stderr, "more\n");
               }
               else {
                 fprintf (stderr, "end\n");
                 break;
               }
               xs_msg_close (part);
           }

SEE ALSO
       xs_msg_data(3) xs_msg_init(3) xs_msg_init_size(3) xs_msg_init_data(3)
       xs_msg_close(3) xs(7)

AUTHORS
       This manual page was written by Chuck Remes <cremes@mac.com[1]>.

NOTES
        1. cremes@mac.com
           mailto:cremes@mac.com

Crossroads I/O 1.2.0              02/17/2016                   XS_GETMSGOPT(3)