These functions operate on the netgroup database file which is described in
netgroup(5).
The database defines a set of netgroups, each made up of one or more triples:
that defines a combination of host, user and domain. Any of the three fields may be specified as ``wildcards'' that match any string.
The function
getnetgrent() sets the three pointer arguments to the strings of the next member of the current netgroup. If any of the string pointers are
NULL that field is considered a wildcard.
The functions
setnetgrent() and
endnetgrent() set the current netgroup and terminate the current netgroup respectively. If
setnetgrent() is called with a different netgroup than the previous call, an implicit
endnetgrent() is implied.
setnetgrent() also sets the offset to the first member of the netgroup.
The function
innetgr() searches for a match of all fields within the specified group. If any of the
host,
user, or
domain arguments are
NULL those fields will match any string value in the netgroup member.