NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | FILES | ATTRIBUTES | CONFORMING TO | SEE ALSO | COLOPHON

GETPROTOENT(3)            Linux Programmer's Manual           GETPROTOENT(3)

NAME         top

       getprotoent,  getprotobyname,  getprotobynumber, setprotoent, endpro‐
       toent - get protocol entry

SYNOPSIS         top

       #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);

DESCRIPTION         top

       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.

RETURN VALUE         top

       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.

FILES         top

       /etc/protocols
              protocol database file

ATTRIBUTES         top

       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(3), getprotoent(3), or endprotoent(3)
       are used in parallel in different threads of a program, then data
       races could occur.

CONFORMING TO         top

       POSIX.1-2001, POSIX.1-2008, 4.3BSD.

SEE ALSO         top

       getnetent(3), getprotoent_r(3), getservent(3), protocols(5)

COLOPHON         top

       This page is part of release 4.07 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                              2015-07-23                   GETPROTOENT(3)