FFI types

This section summarises the types that can be used in definitions for function signatures and field types. The types are split into multiple categories:

Primitive types
Library datatypes
Composed types
Special types
Standard library types

In each category, the table shows the following information:

Description — What the type represents.
Ammer type — How to write the type in definitions.
Haxe call type — What the type will look like from a Haxe client of the ammer library.
Haxe shortcut — Convenience alias for the type using an existing Haxe type, if any.
C type — What the type maps to in a native library/in C language.

With a small number of exceptions, the ammer.ffi.* types exist solely for defining the types of a native library's functions or fields. When an ammer library is used from regular Haxe code, these types turn into a standard Haxe type, the conversion happens automatically. The exceptions are:

ammer.ffi.Array
ammer.ffi.Box
ammer.ffi.Bytes
ammer.ffi.Haxe

Primitive types

Description	Ammer type	Haxe call type	Haxe shortcut	C type
Void	`ammer.ffi.Void`	`Void`	`Void`	`void`
Boolean	`ammer.ffi.Bool`	`Bool`	`Bool`	`bool`
Unsigned 8-bit integer	`ammer.ffi.UInt8`	`UInt`	-	`uint8_t`
Unsigned 16-bit integer	`ammer.ffi.UInt16`	`UInt`	-	`uint16_t`
Unsigned 32-bit integer	`ammer.ffi.UInt32`	`UInt`	`UInt`	`uint32_t`
Unsigned 64-bit integer	`ammer.ffi.UInt64`	`UInt`	-	`uint64_t`
Signed 8-bit integer	`ammer.ffi.Int8`	`Int`	-	`int8_t`
Signed 16-bit integer	`ammer.ffi.Int16`	`Int`	-	`int16_t`
Signed 32-bit integer	`ammer.ffi.Int32`	`Int`	`Int`	`int32_t`
Signed 64-bit integer	`ammer.ffi.Int64`	`Int`	`haxe.Int64`	`int64_t`
Single-precision IEEE 754 number	`ammer.ffi.Float32`	`Single` ¹	`Single` ¹	`float`
Double-precision IEEE 754 number	`ammer.ffi.Float64`	`Float`	`Float`	`double`
String	`ammer.ffi.String`	`String`	`String`	`const char*`

¹: `Single`

Single is only available on some Haxe targets. When a Float32 is used on a target that does not natively support single-precision floating-points, a lossy conversion is used from 64 bits.

Library datatypes

Description	Ammer type	Haxe shortcut	C type
Opaque pointer, struct pointer	-	`T extends Struct ...`	`(type)*`
Opaque data, struct	`ammer.ffi.Deref<T>`	`T extends Struct ...`	`(type)`
Opaque data, struct	`ammer.ffi.Alloc<T>`	`T extends Struct ...`	`(type)`
Haxe object	`ammer.ffi.Haxe<T>`	`T`	`void*`

Composed types

Description	Ammer type	Haxe shortcut	C type
A contiguous array	`ammer.ffi.Array<T>`	-	`(type)*`
Box	`ammer.ffi.Box<T>`	-	`(type)*`
Callback	`ammer.ffi.Callback<...>`	-	-

Special/marker types

Ammer type	Meaning
`ammer.ffi.This`	Stands for the current struct instance, see instance methods
`ammer.ffi.Unsupported<...>`	An unsupported type: the type parameter (a string constant) will be passed to native calls.

Standard library types

Description	Ammer type	C type
File pointer	`ammer.ffi.FilePtr`	`FILE*`