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BINDRESVPORT(3) | Library Functions Manual | BINDRESVPORT(3) |
NAME¶
bindresvport, bindresvport_sa — bind a socket to a privileged IP portLIBRARY¶
Standard C Library (libc, -lc)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 theNULL
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.
SEE ALSO¶
bind(2), getsockopt(2), setsockopt(2), ip(4)November 22, 1987 | Debian |