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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | FILES | ATTRIBUTES | CONFORMING TO | SEE ALSO | COLOPHON |
GETPROTOENT(3) Linux Programmer's Manual GETPROTOENT(3)
getprotoent, getprotobyname, getprotobynumber, setprotoent, endpro‐
toent - get protocol entry
#include <netdb.h>
struct protoent *getprotoent(void);
struct protoent *getprotobyname(const char *name);
struct protoent *getprotobynumber(int proto);
void setprotoent(int stayopen);
void endprotoent(void);
The getprotoent() function reads the next entry from the protocols
database (see protocols(5)) and returns a protoent structure
containing the broken-out fields from the entry. A connection is
opened to the database if necessary.
The getprotobyname() function returns a protoent structure for the
entry from the database that matches the protocol name name. A
connection is opened to the database if necessary.
The getprotobynumber() function returns a protoent structure for the
entry from the database that matches the protocol number number. A
connection is opened to the database if necessary.
The setprotoent() function opens a connection to the database, and
sets the next entry to the first entry. If stayopen is nonzero, then
the connection to the database will not be closed between calls to
one of the getproto*() functions.
The endprotoent() function closes the connection to the database.
The protoent structure is defined in <netdb.h> as follows:
struct protoent {
char *p_name; /* official protocol name */
char **p_aliases; /* alias list */
int p_proto; /* protocol number */
}
The members of the protoent structure are:
p_name The official name of the protocol.
p_aliases
A NULL-terminated list of alternative names for the protocol.
p_proto
The protocol number.
The getprotoent(), getprotobyname() and getprotobynumber() functions
return a pointer to a statically allocated protoent structure, or a
null pointer if an error occurs or the end of the file is reached.
/etc/protocols
protocol database file
For an explanation of the terms used in this section, see
attributes(7).
┌───────────────────┬───────────────┬──────────────────────────────┐
│Interface │ Attribute │ Value │
├───────────────────┼───────────────┼──────────────────────────────┤
│getprotoent() │ Thread safety │ MT-Unsafe race:protoent │
│ │ │ race:protoentbuf locale │
├───────────────────┼───────────────┼──────────────────────────────┤
│getprotobyname() │ Thread safety │ MT-Unsafe race:protobyname │
│ │ │ locale │
├───────────────────┼───────────────┼──────────────────────────────┤
│getprotobynumber() │ Thread safety │ MT-Unsafe race:protobynumber │
│ │ │ locale │
├───────────────────┼───────────────┼──────────────────────────────┤
│setprotoent(), │ Thread safety │ MT-Unsafe race:protoent │
│endprotoent() │ │ locale │
└───────────────────┴───────────────┴──────────────────────────────┘
In the above table, protoent in race:protoent signifies that if any
of the functions setprotoent(), getprotoent(), or endprotoent() are
used in parallel in different threads of a program, then data races
could occur.
POSIX.1-2001, POSIX.1-2008, 4.3BSD.
getnetent(3), getprotoent_r(3), getservent(3), protocols(5)
This page is part of release 4.12 of the Linux man-pages project. A
description of the project, information about reporting bugs, and the
latest version of this page, can be found at
https://www.kernel.org/doc/man-pages/.
GNU 2016-10-08 GETPROTOENT(3)
Pages that refer to this page: getent(1), getsockopt(2), socket(2), getnetent(3), getprotoent_r(3), getservent(3), setnetgrent(3), nsswitch.conf(5), protocols(5), raw(7)