NAME

       bindresvport - bind a socket to a privileged IP port

SYNOPSIS

       #include <sys/types.h>
       #include <netinet/in.h>

       int bindresvport(int sockfd, struct sockaddr_in *sin);

DESCRIPTION

       bindresvport()  is  used  to  bind a socket descriptor to a privileged anonymous IP port, that is, a port
       number arbitrarily selected from the range 512 to 1023.

       If the bind(2) performed by bindresvport() is successful, and sin is not NULL, then sin->sin_port returns
       the port number actually allocated.

       sin can be NULL, in which case sin->sin_family is implicitly taken to be AF_INET.  However, in this case,
       bindresvport() has no way to return the port number actually allocated.  (This information can  later  be
       obtained using getsockname(2).)

RETURN VALUE

       bindresvport()  returns 0 on success; otherwise -1 is returned and errno set to indicate the cause of the
       error.

ERRORS

       bindresvport() can fail for any of the same reasons as bind(2).  In addition, the  following  errors  may
       occur:

       EACCES The caller did not have superuser privilege (to be precise: the CAP_NET_BIND_SERVICE capability is
              required).

       EADDRINUSE
              All privileged ports are in use.

       EAFNOSUPPORT (EPFNOSUPPORT in glibc 2.7 and earlier)
              sin is not NULL and sin->sin_family is not AF_INET.

ATTRIBUTES

   Multithreading (see pthreads(7))
       Before glibc 2.17, the bindresvport() function uses a static variable that is not protected, so it is not
       thread-safe.

       Since  glibc  2.17,  the bindresvport() function uses a lock to protect static variable, so it is thread-
       safe.

CONFORMING TO

       Not in POSIX.1-2001.  Present on the BSDs, Solaris, and many other systems.

NOTES

       Unlike some bindresvport() implementations, the glibc implementation ignores any value  that  the  caller
       supplies in sin->sin_port.

SEE ALSO

       bind(2), getsockname(2)

COLOPHON

       This  page  is  part  of  release 3.54 of the Linux man-pages project.  A description of the project, and
       information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.

                                                   2013-06-21                                    BINDRESVPORT(3)