Writes to a file.

    Format

      #include  <uio.h>

      ssize_t writev  (int file_desc, const struct iovec *iov, int
                      iovcnt);

      ssize_t __writev64  (int file_desc, const struct
                          __iovec64  *iov, int iovcnt);
                          (Integrity servers, Alpha)