NAME

       getservent, getservbyname, getservbyport, setservent, endservent - get service entry

SYNOPSIS

       #include <netdb.h>

       struct servent *getservent(void);

       struct servent *getservbyname(const char *name, const char *proto);

       struct servent *getservbyport(int port, const char *proto);

       void setservent(int stayopen);

       void endservent(void);

DESCRIPTION

       The getservent() function reads the next entry from the services database (see services(5)) and returns a
       servent structure containing the broken-out fields from  the  entry.   A  connection  is  opened  to  the
       database if necessary.

       The getservbyname() function returns a servent structure for the entry from the database that matches the
       service name using protocol proto.  If proto is NULL, any protocol will  be  matched.   A  connection  is
       opened to the database if necessary.

       The getservbyport() function returns a servent structure for the entry from the database that matches the
       port port (given in network byte order) using protocol proto.  If proto is NULL,  any  protocol  will  be
       matched.  A connection is opened to the database if necessary.

       The setservent() 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 getserv*() functions.

       The endservent() function closes the connection to the database.

       The servent structure is defined in <netdb.h> as follows:

           struct servent {
               char  *s_name;       /* official service name */
               char **s_aliases;    /* alias list */
               int    s_port;       /* port number */
               char  *s_proto;      /* protocol to use */
           }

       The members of the servent structure are:

       s_name The official name of the service.

       s_aliases
              A NULL-terminated list of alternative names for the service.

       s_port The port number for the service given in network byte order.

       s_proto
              The name of the protocol to use with this service.

RETURN VALUE

       The  getservent(),  getservbyname()  and  getservbyport()  functions  return  a  pointer  to a statically
       allocated servent structure, or NULL if an error occurs or the end of the file is reached.

FILES

       /etc/services
              services database file

ATTRIBUTES

       For an explanation of the terms used in this section, see attributes(7).

       ┌────────────────┬───────────────┬───────────────────────────┐
       │Interface       │ Attribute     │ Value                     │
       ├────────────────┼───────────────┼───────────────────────────┤
       │getservent()    │ Thread safety │ MT-Unsafe race:servent    │
       │                │               │ race:serventbuf locale    │
       ├────────────────┼───────────────┼───────────────────────────┤
       │getservbyname() │ Thread safety │ MT-Unsafe race:servbyname │
       │                │               │ locale                    │
       ├────────────────┼───────────────┼───────────────────────────┤
       │getservbyport() │ Thread safety │ MT-Unsafe race:servbyport │
       │                │               │ locale                    │
       ├────────────────┼───────────────┼───────────────────────────┤
       │setservent(),   │ Thread safety │ MT-Unsafe race:servent    │
       │endservent()    │               │ locale                    │
       └────────────────┴───────────────┴───────────────────────────┘
       In the above table, servent in  race:servent  signifies  that  if  any  of  the  functions  setservent(),
       getservent(),  or  endservent()  are  used in parallel in different threads of a program, then data races
       could occur.

CONFORMING TO

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

SEE ALSO

       getnetent(3), getprotoent(3), getservent_r(3), services(5)

COLOPHON

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       information   about   reporting   bugs,   and   the  latest  version  of  this  page,  can  be  found  at
       https://www.kernel.org/doc/man-pages/.