BINDRESVPORT(3) 					     Linux Programmer's Manual						   BINDRESVPORT(3)

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  allo-
       cated.

       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 3.53 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)