inet6_rth_space(3)inet6_rth_space(3)NAMEinet6_rth_space - Return the number of bytes required for an IPv6 Rout‐
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 msg_control buffer.
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),
Network Programmer's Guide