bindresvport - bind a socket to a privileged IP port
#include <sys/types.h> #include <netinet/in.h>
int bindresvport(int sd , struct sockaddr_in ** sin );
bindresvport () is used to bind a socket descriptor to a privileged IP port, that is, a port number in the range 0-1023.
If in->sin_port is 0 then an anonymous port in the range 600 to 1023 be chosen. If the bind (2) performed by bindresvport () is successful, 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 and an anonymous port is allocated (as above). However, in this case, bindresvport () has no way to return the port number actually allocated.
bindresvport () returns 0 if it is successful, otherwise -1 is returned and errno set to indicate the cause of the error.
bindresvport () can fail for any of the same reasons as bind (2).
Not in POSIX.1-2001. Present on the BSDs, Solaris, and many other systems.
Only root can bind to a privileged port; this call will fail for any other users. In addition, the following error may occur:
EPFNOSUPPORT sin is not NULL and sin->sin_family is not AF_INET .
bind (2)
