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NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUE | FILES | ATTRIBUTES | STANDARDS | HISTORY | SEE ALSO | COLOPHON |
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getprotoent(3) Library Functions Manual getprotoent(3)
getprotoent, getprotobyname, getprotobynumber, setprotoent,
endprotoent - get protocol entry
Standard C library (libc, -lc)
#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.1-2008.
POSIX.1-2001, 4.3BSD.
getnetent(3), getprotoent_r(3), getservent(3), protocols(5)
This page is part of the man-pages (Linux kernel and C library
user-space interface documentation) project. Information about
the project can be found at
⟨https://www.kernel.org/doc/man-pages/⟩. If you have a bug report
for this manual page, see
⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩.
This page was obtained from the tarball man-pages-6.9.1.tar.gz
fetched from
⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on
2024-06-26. If you discover any rendering problems in this HTML
version of the page, or you believe there is a better or more up-
to-date source for the page, or you have corrections or
improvements to the information in this COLOPHON (which is not
part of the original manual page), send a mail to
man-pages@man7.org
Linux man-pages 6.9.1 2024-05-02 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)
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HTML rendering created 2024-06-26 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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