GNU Info

(libc.info)Netgroup Membership

---

Prev: Lookup Netgroup Up: Netgroup Database

---

Enter node , (file) or (file)node

Testing for Netgroup Membership
-------------------------------

   It is often not necessary to scan the whole netgroup since often the
only interesting question is whether a given entry is part of the
selected netgroup.

 - Function: int innetgr (const char *NETGROUP, const char *HOST, const
          char *USER, const char *DOMAIN)
     This function tests whether the triple specified by the parameters
     HOSTP, USERP, and DOMAINP is part of the netgroup NETGROUP.  Using
     this function has the advantage that

       1. no other netgroup function can use the global netgroup state
          since internal locking is used and

       2. the function is implemented more efficiently than successive
          calls to the other `set'/`get'/`endnetgrent' functions.

     Any of the pointers HOSTP, USERP, and DOMAINP can be `NULL' which
     means any value is accepted in this position.  This is also true
     for the name `-' which should not match any other string otherwise.

     The return value is `1' if an entry matching the given triple is
     found in the netgroup.  The return value is `0' if the netgroup
     itself is not found, the netgroup does not contain the triple or
     internal errors occurred.