### 13.3 Preprocessor Arithmetic

In C99, preprocessor arithmetic, used for `#if`

expressions, must
be evaluated as if all signed values are of type `intmax_t`

and all
unsigned values of type `uintmax_t`

. Many compilers are buggy in
this area, though. For example, as of 2007, Sun C mishandles ```
#if
LLONG_MIN < 0
```

on a platform with 32-bit `long int`

and 64-bit
`long long int`

. Also, some older preprocessors mishandle
constants ending in `LL`

. To work around these problems, you can
compute the value of expressions like `LONG_MAX < LLONG_MAX`

at
`configure`

-time rather than at `#if`

-time.