$NetBSD: bindresvport.3,v 1.8 2000/07/05 15:45:33 msaitoh Exp $
$FreeBSD$
.Dd November 22, 1987 .Dt BINDRESVPORT 3 .Os .Sh NAME .Nm bindresvport , .Nm bindresvport_sa .Nd bind a socket to a privileged IP port .Sh LIBRARY .Lb libc .Sh SYNOPSIS n sys/types.h n rpc/rpc.h .Ft int .Fn bindresvport "int sd" "struct sockaddr_in *sin" .Ft int .Fn bindresvport_sa "int sd" "struct sockaddr *sa" .Sh DESCRIPTION The .Fn bindresvport and .Fn bindresvport_sa functions are used to bind a socket descriptor to a privileged .Tn IP port, that is, a port number in the range 0-1023.
p If .Fa sin is a pointer to a .Ft "struct sockaddr_in" then the appropriate fields in the structure should be defined. Note that .Fa sin->sin_family must be initialized to the address family of the socket, passed by .Fa sd . If .Fa sin->sin_port is .Sq 0 then an anonymous port (in the range 600-1023) will be chosen, and if .Xr bind 2 is successful, the .Fa sin->sin_port will be updated to contain the allocated port.
p If .Fa sin is the .Dv NULL pointer, an anonymous port will be allocated (as above). However, there is no way for .Fn bindresvport to return the allocated port in this case.
p Only root can bind to a privileged port; this call will fail for any other users.
p Function prototype of .Fn bindresvport is biased to .Dv AF_INET socket. The .Fn bindresvport_sa function acts exactly the same, with more neutral function prototype. Note that both functions behave exactly the same, and both support .Dv AF_INET6 sockets as well as .Dv AF_INET sockets. .Sh RETURN VALUES .Rv -std bindresvport .Sh ERRORS l -tag -width Er t Bq Er EPFNOSUPPORT If second argument was supplied, and address family did not match between arguments. .El
p The .Fn bindresvport function may also fail and set .Va errno for any of the errors specified for the calls .Xr bind 2 , .Xr getsockopt 2 , or .Xr setsockopt 2 . .Sh SEE ALSO .Xr bind 2 , .Xr getsockopt 2 , .Xr setsockopt 2 , .Xr ip 4