getservbyport - Always returning NULL servent Post: 302272750

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LEARN ABOUT LINUX

getservbyname

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

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 a NULL
       pointer if an error occurs or the end of the file is reached.

FILES

       /etc/services
	      services database file

CONFORMING TO

       4.3BSD, POSIX.1-2001.

SEE ALSO

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

COLOPHON

       This page is part of release 3.27 of the Linux man-pages project.  A description of the project, and information about reporting bugs,  can
       be found at http://www.kernel.org/doc/man-pages/.

GNU
								    2008-08-19							     GETSERVENT(3)