ENDNETENT(P) POSIX Programmer's Manual ENDNETENT(P)
endnetent, getnetbyaddr, getnetbyname, getnetent, setnetent - network database functions
struct netent *getnetbyaddr(uint32_t net, int type);
struct netent *getnetbyname(const char *name);
struct netent *getnetent(void);
void setnetent(int stayopen);
These functions shall retrieve information about networks. This information is considered
to be stored in a database that can be accessed sequentially or randomly. The implementa-
tion of this database is unspecified.
The setnetent() function shall open and rewind the database. If the stayopen argument is
non-zero, the connection to the net database shall not be closed after each call to getne-
tent() (either directly, or indirectly through one of the other getnet*() functions), and
the implementation may maintain an open file descriptor to the database.
The getnetent() function shall read the next entry of the database, opening and closing a
connection to the database as necessary.
The getnetbyaddr() function shall search the database from the beginning, and find the
first entry for which the address family specified by type matches the n_addrtype member
and the network number net matches the n_net member, opening and closing a connection to
the database as necessary. The net argument shall be the network number in host byte
The getnetbyname() function shall search the database from the beginning and find the
first entry for which the network name specified by name matches the n_name member, open-
ing and closing a connection to the database as necessary.
The getnetbyaddr(), getnetbyname(), and getnetent() functions shall each return a pointer
to a netent structure, the members of which shall contain the fields of an entry in the
The endnetent() function shall close the database, releasing any open file descriptor.
These functions need not be reentrant. A function that is not required to be reentrant is
not required to be thread-safe.
Upon successful completion, getnetbyaddr(), getnetbyname(), and getnetent() shall return a
pointer to a netent structure if the requested entry was found, and a null pointer if the
end of the database was reached or the requested entry was not found. Otherwise, a null
pointer shall be returned.
No errors are defined.
The following sections are informative.
The getnetbyaddr(), getnetbyname(), and getnetent() functions may return pointers to
static data, which may be overwritten by subsequent calls to any of these functions.
The Base Definitions volume of IEEE Std 1003.1-2001, <netdb.h>
Portions of this text are reprinted and reproduced in electronic form from IEEE Std
1003.1, 2003 Edition, Standard for Information Technology -- Portable Operating System
Interface (POSIX), The Open Group Base Specifications Issue 6, Copyright (C) 2001-2003 by
the Institute of Electrical and Electronics Engineers, Inc and The Open Group. In the
event of any discrepancy between this version and the original IEEE and The Open Group
Standard, the original IEEE and The Open Group Standard is the referee document. The orig-
inal Standard can be obtained online at http://www.opengroup.org/unix/online.html .
IEEE/The Open Group 2003 ENDNETENT(P)