1.\" @(#)bindresvport.3n 2.2 88/08/02 4.0 RPCSRC; from 1.7 88/03/14 SMI 2.Dd November 22, 1987 3.Dt BINDRESVPORT 3 4.Os 5.Sh NAME 6.Nm bindresvport 7.Ndbind a socket to a privileged IP port 8.Sh SYNOPSIS 9.Fd #include <sys/types.h> 10.Fd #include <netinet/in.h> 11.Ft int 12.Fn bindresvport "int sd" "struct sockaddr_in **sin" 13.Sh DESCRIPTION 14.Nm Bindresvport 15is used to bind a socket descriptor to a privileged 16.Tn IP 17port, that is, a 18port number in the range 0-1023. 19The routine returns 0 if it is successful, 20otherwise -1 is returned and 21.Va errno 22set to reflect the cause of the error. 23.Pp 24Only root can bind to a privileged port; this call will fail for any 25other users. 26.Pp 27If the value of sin->sin_port is non-zero 28.Fn bindresvport 29will attempt to use that specific port. If it fails, it chooses another 30privileged port automatically. 31