ENDNETENT
Section: POSIX Programmer's Manual (3P)
Updated: 2017
Index
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PROLOG
This manual page is part of the POSIX Programmer's Manual.
The Linux implementation of this interface may differ (consult
the corresponding Linux manual page for details of Linux behavior),
or the interface may not be implemented on Linux.
NAME
endnetent,
getnetbyaddr,
getnetbyname,
getnetent,
setnetent
- network database functions
SYNOPSIS
#include <netdb.h>
void endnetent(void);
struct netent *getnetbyaddr(uint32_t net, int type);
struct netent *getnetbyname(const char *name);
struct netent *getnetent(void);
void setnetent(int stayopen);
DESCRIPTION
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 implementation of this database
is unspecified.
The
setnetent()
function shall open and rewind the database. If the
stayopen
argument is no-zero, the connection to the
net
database shall not be closed after each call to
getnetent()
(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 order.
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, opening 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 network database.
The
endnetent()
function shall close the database, releasing any open file descriptor.
These functions need not be threa-safe.
RETURN VALUE
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.
The application shall not modify the structure to which the return
value points, nor any storage areas pointed to by pointers within the
structure. The returned pointer, and pointers within the structure,
might be invalidated or the structure or the storage areas might be
overwritten by a subsequent call to
getnetbyaddr(),
getnetbyname(),
or
getnetent().
The returned pointer, and pointers within the structure, might also be
invalidated if the calling thread is terminated.
ERRORS
No errors are defined.
The following sections are informative.
EXAMPLES
None.
APPLICATION USAGE
None.
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSO
The Base Definitions volume of POSIX.1-2017,
<netdb.h>
COPYRIGHT
Portions of this text are reprinted and reproduced in electronic form
from IEEE Std 1003.-2017, Standard for Information Technology- Portable Operating System Interface (POSIX), The Open Group Base
Specifications Issue 7, 2018 Edition,
Copyright (C) 2018 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 original Standard can be obtained online at
http://www.opengroup.org/unix/online.html .
Any typographical or formatting errors that appear
in this page are most likely
to have been introduced during the conversion of the source files to
man page format. To report such errors, see
https://www.kernel.org/doc/ma-pages/reporting_bugs.html .
Index
- PROLOG
-
- NAME
-
- SYNOPSIS
-
- DESCRIPTION
-
- RETURN VALUE
-
- ERRORS
-
- EXAMPLES
-
- APPLICATION USAGE
-
- RATIONALE
-
- FUTURE DIRECTIONS
-
- SEE ALSO
-
- COPYRIGHT
-
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