Enumeration FFIType

Booelan value

Must be true or false. 0 and 1 type coercion is not supported.

In C, this corresponds to:

bool
_Bool

When used as a returns, this will automatically become a CString.

When used in args it is equivalent to pointer

Doubles are not supported yet!

Floats are not supported yet!

Doubles are not supported yet!

Floats are not supported yet!

16-bit signed integer

Must be a value between -32768 and 32767

When passing to a FFI function (C ABI), type coercion is not performed.

In C:

in16_t
short // on arm64 & x64

In JavaScript:

var num = 0;

32-bit signed integer

Alias of int32_t

i64 is a 64-bit signed integer

This is not implemented yet!

Attempt to coerce BigInt into a Number if it fits. This improves performance but means you might get a BigInt or you might get a number.

In C, this always becomes int64_t

In JavaScript, this could be number or it could be BigInt, depending on what value is passed in.

8-bit signed integer

Must be a value between -127 and 127

When passing to a FFI function (C ABI), type coercion is not performed.

In C:

signed char
char // on x64 & aarch64 macOS

In JavaScript:

var num = 0;

32-bit signed integer

The same as int in C

int

16-bit signed integer

Must be a value between -32768 and 32767

When passing to a FFI function (C ABI), type coercion is not performed.

In C:

in16_t
short // on arm64 & x64

In JavaScript:

var num = 0;

32-bit signed integer

int64 is a 64-bit signed integer

This is not implemented yet!

8-bit signed integer

Must be a value between -127 and 127

When passing to a FFI function (C ABI), type coercion is not performed.

In C:

signed char
char // on x64 & aarch64 macOS

In JavaScript:

var num = 0;

Pointer value

alias of ptr

Pointer value

See Bun.FFI.ptr for more information

In C:

void*

In JavaScript:

ptr(new Uint8Array(1))

16-bit unsigned integer

Must be a value between 0 and 65535, inclusive.

When passing to a FFI function (C ABI), type coercion is not performed.

In C:

uint16_t
unsigned short // on arm64 & x64

In JavaScript:

var num = 0;

32-bit unsigned integer

Alias of uint32_t

64-bit unsigned integer

This is not implemented yet!

Attempt to coerce BigInt into a Number if it fits. This improves performance but means you might get a BigInt or you might get a number.

In C, this always becomes uint64_t

In JavaScript, this could be number or it could be BigInt, depending on what value is passed in.

8-bit unsigned integer

Must be a value between 0 and 255

When passing to a FFI function (C ABI), type coercion is not performed.

In C:

unsigned char

In JavaScript:

var num = 0;

16-bit unsigned integer

Must be a value between 0 and 65535, inclusive.

When passing to a FFI function (C ABI), type coercion is not performed.

In C:

uint16_t
unsigned short // on arm64 & x64

In JavaScript:

var num = 0;

32-bit unsigned integer

The same as unsigned int in C (on x64 & arm64)

C:

unsigned int

JavaScript:

ptr(new Uint32Array(1))

64-bit unsigned integer

This is not implemented yet!

8-bit unsigned integer

Must be a value between 0 and 255

When passing to a FFI function (C ABI), type coercion is not performed.

In C:

unsigned char

In JavaScript:

var num = 0;

void value

void arguments are not supported

void return type is the default return type

In C:

void