ENDPROTOENT
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
endprotoent,
getprotobyname,
getprotobynumber,
getprotoent,
setprotoent
- network protocol database functions
SYNOPSIS
#include <netdb.h>
void endprotoent(void);
struct protoent *getprotobyname(const char *name);
struct protoent *getprotobynumber(int proto);
struct protoent *getprotoent(void);
void setprotoent(int stayopen);
DESCRIPTION
These functions shall retrieve information about protocols. 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
setprotoent()
function shall open a connection to the database, and set the next
entry to the first entry. If the
stayopen
argument is no-zero, the connection to the network protocol database
shall not be closed after each call to
getprotoent()
(either directly, or indirectly through one of the other
getproto*()
functions), and the implementation may maintain an open file descriptor
for the database.
The
getprotobyname()
function shall search the database from the beginning and find the
first entry for which the protocol name specified by
name
matches the
p_name
member, opening and closing a connection to the database as necessary.
The
getprotobynumber()
function shall search the database from the beginning and find the
first entry for which the protocol number specified by
proto
matches the
p_proto
member, opening and closing a connection to the database as necessary.
The
getprotoent()
function shall read the next entry of the database, opening and closing
a connection to the database as necessary.
The
getprotobyname(),
getprotobynumber(),
and
getprotoent()
functions shall each return a pointer to a
protoent
structure, the members of which shall contain the fields of an entry in
the network protocol database.
The
endprotoent()
function shall close the connection to the database, releasing any
open file descriptor.
These functions need not be threa-safe.
RETURN VALUE
Upon successful completion,
getprotobyname(),
getprotobynumber(),
and
getprotoent()
return a pointer to a
protoent
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 is 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
getprotobyname(),
getprotobynumber(),
or
getprotoent().
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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