NAME

       bindresvport, bindresvport_sa — bind a socket to a privileged IP port

SYNOPSIS

       #include <sys/types.h>
       #include <rpc/rpc.h>

       int
       bindresvport(int sd, struct sockaddr_in *sin);

       int
       bindresvport_sa(int sd, struct sockaddr *sa);

DESCRIPTION

       The  bindresvport()  and bindresvport_sa() functions are used to bind a socket descriptor to a privileged
       IP port, that is, a port number in the range 0-1023.

       If sin is a pointer to a struct sockaddr_in then the  appropriate  fields  in  the  structure  should  be
       defined.   Note  that  sin->sin_family must be initialized to the address family of the socket, passed by
       sd.  If sin->sin_port is ‘0’ then an anonymous port (in the  range  600-1023)  will  be  chosen,  and  if
       bind(2) is successful, the sin->sin_port will be updated to contain the allocated port.

       If sin is the NULL pointer, an anonymous port will be allocated (as above).  However, there is no way for
       bindresvport() to return the allocated port in this case.

       Only root can bind to a privileged port; this call will fail for any other users.

       Function  prototype  of  bindresvport() is biased to AF_INET socket.  The bindresvport_sa() function acts
       exactly the same, with more neutral function prototype.  Note that  both  functions  behave  exactly  the
       same, and both support AF_INET6 sockets as well as AF_INET sockets.

RETURN VALUES

       The bindresvport() function returns the value 0 if successful; otherwise the value -1 is returned and the
       global variable errno is set to indicate the error.

ERRORS

       [EPFNOSUPPORT]     If second argument was supplied, and address family did not match between arguments.

       The  bindresvport()  function  may  also fail and set errno for any of the errors specified for the calls
       bind(2), getsockopt(2), or setsockopt(2).

AVAILABILITY

       The bindresvport() function is part of libtirpc.

SEE ALSO

       bind(2), getsockopt(2), setsockopt(2)

Debian                                          November 22, 1987                                BINDRESVPORT(3)