inet6_rth_space - Return the number of bytes required for
an IPv6 Routing header
int segments );
Standard C Library (libc)
Specifies the type of Routing header. The valid value is
IPV6_RTHDR_TYPE_0 for IPv6 Routing header type 0. Specifies
the number of segments or addresses that are to be
included in the Routing header. The valid value is from 0
to 127, inclusive.
The inet6_rth_space() function determines the amount of
space, in bytes, required for a Routing header. Although
the function returns the amount of space required, it does
not allocate buffer space. This enables the application to
allocate a larger buffer.
If the application uses ancillary data, it must pass the
returned length to CMSG_LEN() to determine the amount of
memory required for the ancillary data object, including
the cmsghdr structure.
If an application wants to send other ancillary data
objects, it must specify them to sendmsg() as a single
Upon successful completion, the inet6_rth_space() function
returns the length, in bytes, of the Routing header and
the specified number of segments. If the type is not supported
or the number of segments is invalid for the type
of Routing header, the function returns 0.
Functions: inet6_rth_add(3), inet6_rth_getaddr(3),
inet6_rth_init(3), inet6_rth_reverse(3), inet6_rth_segments(3).
Network Programmer's Guide
[ Back ]