FFIType

enum FFIType

• bool

  Boolean value

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

  In C, this corresponds to:

  bool
  _Bool
  
• buffer
• char
• cstring

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

  When used in args it is equivalent to FFIType.pointer

• double

  Doubles are not supported yet!

• f32

  Floats are not supported yet!

• f64

  Doubles are not supported yet!

• float

  Floats are not supported yet!

• function
• i16

  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;
  
• i32

  32-bit signed integer

  Alias of FFIType.int32_t

• i64

  i64 is a 64-bit signed integer

  This is not implemented yet!

• i64_fast

  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.

• i8

  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;
  
• int

  32-bit signed integer

  The same as int in C

  int
  
• int16_t

  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;
  
• int32_t

  32-bit signed integer

• int64_t

  int64 is a 64-bit signed integer

  This is not implemented yet!

• int8_t

  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;
  
• napi_env
• napi_value
• pointer

  Pointer value

  alias of FFIType.ptr

• ptr

  Pointer value

  See Bun.FFI.ptr for more information

  In C:

  void*
  

  In JavaScript:

  ptr(new Uint8Array(1))
  
• u16

  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;
  
• u32

  32-bit unsigned integer

  Alias of FFIType.uint32_t

• u64

  64-bit unsigned integer

  This is not implemented yet!

• u64_fast

  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.

• u8

  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;
  
• uint16_t

  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;
  
• uint32_t

  32-bit unsigned integer

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

  C:

  unsigned int
  

  JavaScript:

  ptr(new Uint32Array(1))
  
• uint64_t

  64-bit unsigned integer

  This is not implemented yet!

• uint8_t

  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

  void value

  void arguments are not supported

  void return type is the default return type

  In C:

  void