Find the next IPv6 hop-by-hop or destination option
#include <netinet/in.h> int inet6_option_next(const struct cmsghdr *cmsg, u_int8_t **tptrp);
Use the -l socket option to qcc to link against this library.
This inet6_option_next() function finds the next hop-by-hop option or destination option in an ancillary data object. If another option remains to be processed, the return value of the function is 0 and *tptrp points to the 8-bit option type field the option data.
The cmsg variable is a pointer to cmsghdr structure for which cmsg_level equals IPPROTO_IPV6 and cmsg_type equals either IPV6_HOPOPTS or IPV6_DSTOPTS.
The tptrp is a pointer to a pointer to an 8-bit byte and *tptrp is used by the function to remember its place in the ancillary data object each time the function is called. The first time you call this function for a given ancillary data object, you must set *tptrp to NULL.
Each time this function returns success, *tptrp points to the 8-bit option type field for the next option to be processed.
inet6_option_alloc(), inet6_option_append(), inet6_option_find(), inet6_option_init(), inet6_option_space()