BINDRESVPORTSection: Linux Programmer's Manual (3)
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NAMEbindresvport - bind a socket to a privileged IP port
#include <sys/types.h> #include <netinet/in.h> int bindresvport(int sockfd, struct sockaddr_in *sin);
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 VALUEbindresvport() returns 0 on success; otherwise -1 is returned and errno set to indicate the cause of the error.
ERRORSbindresvport() can fail for any of the same reasons as bind(2). In addition, the following errors may occur:
- The caller did not have superuser privilege (to be precise: the CAP_NET_BIND_SERVICE capability is required).
- 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.
CONFORMING TONot in POSIX.1-2001. Present on the BSDs, Solaris, and many other systems.
NOTESUnlike some bindresvport() implementations, the glibc implementation ignores any value that the caller supplies in sin->sin_port.
SEE ALSObind(2), getsockname(2)
COLOPHONThis page is part of release 3.21 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/.