0                  Indicates success.
    -1                 Indicates an error; errno is set to one of the
                       following values:

                       o  EACCESS - The prot argument specifies a
                          protection that conflicts with the access
                          permission set for the underlying file.

                       o  EINVAL - The prot argument is invalid, or
                          the addr argument is not a multiple of the
                          page size as returned by sysconf(_SC_PAGE_
                          SIZE).

                       o  EFAULT - The range [addr, addr + len]
                          includes an invalid address.