How to define a type like size_t??

[JsouLiang]

JavaScriptCore has a API is JSStringGetLength it need a JSStringRef and return a size_t type value.

size_t : if the compiler is 32 bit then it is simply a typedef(i.e., alias) for unsigned int but if the compiler is 64 bit then it would be a typedef for unsigned long long. The size_t data type is never negative.

dart.ffi has ffi.Uint32, ffi.Uint64, witch type should I use to map size_t? If I use ffi.Uint64 it has a out of bound problem is 32bit machine. I think this problem because in 32bit matchine C API return a 32bit size value, but ffi.Pointer it will find UInt64 size value. If I use Uint32 in 64bit matchine when the return value is so large may be out of bound.
How to define a type in 32bit matchine is Uint32 and 64bit is Uint64 like size_t??

[ds84182]

You can use ffi.IntPtr for this. However, I think it gets sign extended on both 32-bit and 64-bit machines.

[JsouLiang]

I find some package is use Int32 like this: tflite_native, method: TfLiteTensorByteSize
and some package is use IntPtr like this: malloc, malloc : void* malloc(size_t __byte_count)
I want know what different of them?? Thanks😁

[ds84182]

@x-liang The TFLite one seems like a bug. It should be IntPtr, otherwise if the size is greater than 2gb the return result will be incorrect.

[dcharkes]

It's not possible to define your own native type that way.

We keep track of a list of requested types here: #36140. Though, we can only add those types if they are well-defined across a range of compilers/platforms.

[dcharkes]

We've filed an issue for implementing a generic solution for this #42563.