The basic integer types at various sizes. The s or u prefix specifies a signed or an unsigned integer, respectively; the ones with no prefix are signed.

The _sbyte and _ubyte types are aliases for _sint8 and _uint8, respectively. The _byte type is like _ubyte, but adds 256 to a negative Racket value that would work as a _sbyte (i.e., it casts signed bytes to unsigned bytes).

The _sword and _uword types are aliases for _sint16 and _uint16, respectively. The _word type is like _uword, but coerces negative values in the same way as _byte.

Aliases for basic integer types. The _short aliases correspond to _int16. The _int aliases correspond to _int32. The _long aliases correspond to either _int32 or _int64, depending on the platform. Similarly, the _intptr aliases correspond to either _int32 or _int64, depending on the platform.

For cases where speed matters and where you know that the integer is small enough, the types _fixnum and _ufixnum are similar to _intptr and _uintptr but assume that the quantities fit in Racket’s immediate integers (i.e., not bignums).

Similar to _fixnum/_ufixnum, but based on _int/_uint instead of _intptr/_uintptr, and coercions from C are checked to be in range.

The _float and _double types represent the corresponding C types. Both single- and double-precision Racket numbers are accepted for conversion via both _float and _double, while both _float and _double coerce C values to double-precision Racket numbers. The type _double* coerces any Racket real number to a C double.