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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
06/13/2012 Crossroads I/O 1.2.0