$FreeBSD: head/lib/libc/rpc/bindresvport.3 56629 2000-01-26 09:02:42Z shin $
.Dd November 22, 1987 .Dt BINDRESVPORT 3 .Os .Sh NAME .Nm bindresvport , .Nm bindresvport_sa , .Ndbind a socket to a privileged IP port .Sh SYNOPSIS .Fd #include <sys/types.h> .Fd #include <netinet/in.h> .Ft int .Fn bindresvport "int sd" "struct sockaddr_in *sin" .Ft int .Fn bindresvport_sa "int sd" "struct sockaddr *sa" .Sh DESCRIPTION .Nm Bindresvport and .Nm Bindresvport_sa are used to bind a socket descriptor to a privileged .Tn IP port, that is, a port number in the range 0-1023.
p Only root can bind to a privileged port; this call will fail for any other users.
p When .Va sin is not null, .Va sin->sin_family must be initialized to the address family of the socket, passed by .Va sd . If the value of sin->sin_port is non-zero .Fn bindresvport will attempt to use that specific port. If it fails, it chooses another privileged port automatically.
p It is legal to pass null pointer to .Va sin . In this case, the caller cannot get the port number .Fn bindresvport has picked.
p Function prototype of .Fn bindresvport is biased to .Dv AF_INET socket. .Fn bindresvport_sa 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 .Fn bindresvport returns 0 if it is successful, otherwise -1 is returned and .Va errno set to reflect the cause of the error. .Sh ERRORS The .Fn bindresvport function fails if: l -tag -width Er t Bq Er EBADF .Fa sd is not a valid descriptor. t Bq Er ENOTSOCK .Fa sd is not a socket. t Bq Er EADDRNOTAVAIL The specified address is not available from the local machine. t Bq Er EADDRINUSE The specified address is already in use. t Bq Er EINVAL The socket is already bound to an address, or the socket family and the family of specified address mismatch. t Bq Er EACCES The requested address is protected, and the current user has inadequate permission to access it. t Bq Er EFAULT The .Fa name parameter is not in a valid part of the user address space. t Bq Er ENOBUFS Insufficient resources were available in the system to perform the operation. t Bq Er EPFNOSUPPORT The protocol family has not been configured into the system, no implementation for it exists, or address family did not match between arguments. .El .Sh "SEE ALSO" .Xr bind 2 , .Xr socket 2 , .Xr rresvport 3 , .Xr rresvport_af 3