bindresvport(3) bind a socket to a privileged IP port

Other Alias



In sys/types.h In rpc/rpc.h Ft int Fn bindresvport int sd struct sockaddr_in *sin Ft int Fn bindresvport_sa int sd struct sockaddr *sa


The Fn bindresvport and Fn 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 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 `0' then an anonymous port (in the range 600-1023) will be chosen, and if bind(2) is successful, the Fa sin->sin_port will be updated to contain the allocated port.

If Fa sin is the 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.

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

Function prototype of Fn bindresvport is biased to 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 AF_INET6 sockets as well as AF_INET sockets.


Rv -std bindresvport


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

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


The Fn bindresvport function is part of libtirpc.