REALHOSTNAME(3) BSD Library Functions Manual REALHOSTNAME(3)NAMErealhostname — convert an IP number to the real host name
System Utilities Library (libutil, -lutil)
realhostname(char *host, size_t hsize, const struct in_addr *ip);
The function realhostname() converts ip to the corresponding host name.
This is done by resolving ip to a host name and then ensuring that the
host name resolves back to ip.
host must point to a buffer of at least hsize bytes, and will always be
written to by this function.
If the name resolution does not work both ways or if the host name is
longer than hsize bytes, inet_ntoa(3) is used to convert ip to an ASCII
If the string written to host is hsize bytes long, host will not be NUL
The realhostname() function will return one of the following constants
which are defined in <libutil.h>:
A valid host name was found.
A host name was found, but it did not resolve back to the passed
ip. host now contains the numeric value of ip.
ip could not be resolved. host now contains the numeric value of
A host name was found, but it could not be resolved back to any
ip number. host now contains the numeric value of ip.
SEE ALSOgethostbyaddr(3), gethostbyname(3), inet_ntoa(3), realhostname_sa(3)BSD April 6, 1999 BSD