getservent

GETSERVENT(3)            BSD Library Functions Manual            GETSERVENT(3)

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

SYNOPSIS
     #include <netdb.h>

     struct servent *
     getservent(void);

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

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

     void
     setservent(int stayopen);

     void
     endservent(void);

DESCRIPTION
     The getservent(), getservbyname(), and getservbyport() functions each
     return a pointer to an object with the following structure containing the
     broken-out fields of a line in the network services database,
     /etc/services.

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

     The members of this structure are:

     s_name     The official name of the service.

     s_aliases  A zero-terminated list of alternate names for the service.

     s_port     The port number at which the service resides.  Port numbers
                are returned in network byte order.

     s_proto    The name of the protocol to use when contacting the service.

     The getservent() function reads the next line of the file, opening the
     file if necessary.

     The setservent() function opens and rewinds the file.  If the stayopen
     flag is non-zero, the net database will not be closed after each call to
     getservbyname() or getservbyport().

     The endservent() function closes the file.

     The getservbyname() and getservbyport() functions sequentially search
     from the beginning of the file until a matching protocol name or port
     number (specified in network byte order) is found, or until EOF is
     encountered.  If a protocol name is also supplied (non-null), searches
     must also match the protocol.

FILES
     /etc/services

DIAGNOSTICS
     Null pointer (0) returned on EOF or error.

SEE ALSO
     getprotoent(3), services(5)

HISTORY
     The getservent(), getservbyport(), getservbyname(), setservent(), and
     endservent() functions appeared in 4.2BSD.

BUGS
     These functions use static data storage; if the data is needed for future
     use, it should be copied before any subsequent calls overwrite it.
     Expecting port numbers to fit in a 32-bit quantity is probably naive.

BSD                            January 12, 1994                            BSD
    
2017-02-09
Documentation license for this page: Open Publication License