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 non-
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 reentrant. A function that is not required
to be reentrant is not required to be thread-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.
ERRORS
No errors are defined.
The following sections are informative.
EXAMPLES
None.
APPLICATION USAGE
The getprotobyname(), getprotobynumber(), and getprotoent() functions
may return pointers to static data, which may be overwritten by
subsequent calls to any of these functions.
RATIONALE
None.
FUTURE DIRECTIONS
None.
SEE ALSO
The Base Definitions volume of IEEE Std 1003.1-2001, <netdb.h>
COPYRIGHT
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 original Standard can be obtained online
at http://www.opengroup.org/unix/online.html .