ENDPROTOENT(P) POSIX Programmer's Manual ENDPROTOENT(P)
endprotoent, getprotobyname, getprotobynumber, getprotoent, setprotoent - network protocol
struct protoent *getprotobyname(const char *name);
struct protoent *getprotobynumber(int proto);
struct protoent *getprotoent(void);
void setprotoent(int stayopen);
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 implementa-
tion 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, open-
ing 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
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, 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.
No errors are defined.
The following sections are informative.
The getprotobyname(), getprotobynumber(), and getprotoent() 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 ENDPROTOENT(P)