getservent(3) — Linux manual page

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

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

NAME         top

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

SYNOPSIS         top

       #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         top

       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         top

       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         top

       /etc/services
              services database file

ATTRIBUTES         top

       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 locale │
       │endservent()    │               │                               │
       └────────────────┴───────────────┴───────────────────────────────┘
       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         top

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

SEE ALSO         top

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

COLOPHON         top

       This page is part of release 5.11 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                  GETSERVENT(3)

Pages that refer to this page: getent(1)byteorder(3)getaddrinfo(3)getnameinfo(3)getnetent(3)getprotoent(3)getservent_r(3)rexec(3)setnetgrent(3)nss(5)nsswitch.conf(5)services(5)