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Types
Deno FFI supports the following types:
| Type declaration | JavaScript | Description |
|---|---|---|
"bool" |
boolean |
Boolean value |
"u8" |
number |
8-bit (one byte) unsigned integer |
"i8" |
number |
8-bit (one byte) signed integer |
"u16" |
number |
16-bit (two byte) unsigned integer |
"i16" |
number |
16-bit (two byte) signed integer |
"u32" |
number |
32-bit (four byte) unsigned integer |
"i32" |
number |
32-bit (four byte) signed integer |
"u64" |
number | bigint |
64-bit (eight byte) unsigned integer |
"i64" |
number | bigint |
64-bit (eight byte) signed integer |
"f32" |
number | bigint |
32-bit (four byte) IEEE 754 floating point number |
"f64" |
number | bigint |
64-bit (eight byte) IEEE 754 floating point number |
"usize" |
number | bigint |
Pointer size unsigned integer |
"isize" |
number | bigint |
Pointer size signed integer |
"buffer" |
Uint8Array (or ArrayBuffer, or any other TypedArray) |
Generic JavaScript buffer |
"pointer" |
null | {} (pointer object) |
Generic pointer |
"function" |
null | {} |
Generic function pointer |
{ "struct": [...] } |
Uint8Array (or ArrayBuffer, or any other TypedArray) |
Struct-by-value with given fields |
The actual size of "pointer size" depends on the bitness of the environments. 32-bit computers will have 32-bit pointers and 64-bit computers will have 64-bit pointers. Currently Deno only supports 64-bit environments but this may change in the future.