tail head cat sleep
QR code linking to this page

Manual Pages  — GETNETGRENT


getnetgrent, innetgr, setnetgrent, endnetgrent – netgroup database operations



Standard C Library (libc, -lc)


#include <netdb.h>

getnetgrent(char **host, char **user, char **domain);

getnetgrent_r(char **host, char **user, char **domain, char *buf, size_t bufsize);

innetgr(const char *netgroup, const char *host, const char *user, const char *domain);

setnetgrent(const char *netgroup);



These functions operate on the netgroup database file /etc/netgroup which is described in netgroup(5). The database defines a set of netgroups, each made up of one or more triples:
(host, user, domain)
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. The setnetgrent() function 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.


The function getnetgrent() returns 0 for ``no more netgroup members'' and 1 otherwise. The function innetgr() returns 1 for a successful match and 0 otherwise. The functions setnetgrent() and endnetgrent() have no return value.


  netgroup database file


The netgroup members have three string fields to maintain compatibility with other vendor implementations, however it is not obvious what use the domain string has within BSD .




The function getnetgrent() returns pointers to dynamically allocated data areas that are freed when the function endnetgrent() is called.

GETNETGRENT (3) June 5, 2016

tail head cat sleep
QR code linking to this page

Please direct any comments about this manual page service to Ben Bullock. Privacy policy.

This philosophy, in the hands of amateurs, leads to inexplicably mind-numbing botches like the existence of two programs, “head” and “tail,” which print the first part or the last part of a file, depending. Even though their operations are duals of one another, “head” and “tail” are different programs, written by different authors, and take different options!
— The Unix Haters' handbook