check_for
return check_for(msb, nr, nr, 0);
return check_for(msb, nr, nr, -ENOSYS);
check_for(msb, -64, -2, -ENOSYS);
check_for(msb, -1, -1, MODIFIED_BY_PTRACE);
check_for(msb, -1, -1, -ENOSYS);
check_for(msb, X32_BIT-64, X32_BIT-1, -ENOSYS);
check_for(msb, -64-X32_BIT, -1-X32_BIT, -ENOSYS);
check_for(msb, INT_MAX-64, INT_MAX-1, -ENOSYS);
check_for(msb, 512, 547, -ENOSYS);
check_for(msb, 0 | X32_BIT, 999 | X32_BIT, -ENOSYS);