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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | FILES | ATTRIBUTES | CONFORMING TO | SEE ALSO | COLOPHON |
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GETPROTOENT(3) Linux Programmer's Manual GETPROTOENT(3)
getprotoent, getprotobyname, getprotobynumber, setprotoent,
endprotoent - 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 5.13 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 2021-03-22 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)
Copyright and license for this manual page
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