Flutter how to create boolean field in mapped Struct using FFIGen

Question

I'm trying to using latest FFIGEN (11.0.0) and almost latest Flutter 3.16.4 (dart 3.2.3)

This my my struct in C++

struct TestStruct {
    const char *name;
    bool isOnline;
    uint8_t batteryLevel;
    uint32_t timestamp;
};

And this is exported using

extern "C" struct TestStruct;

The problem is that every time I run FFIGEN it generates

final class TestStruct extends ffi.Struct {
  external ffi.Pointer<ffi.Char> name;

  @ffi.Int()
  external int isOnline;

  @ffi.Uint8()
  external int batteryLevel;

  @ffi.Uint32()
  external int timestamp;
}

I have to manually change boolean entry to:

  @ffi.Bool()
  external bool isOnline;

I even tried to leave it and map int to bool later, but dart object is not correct.

Any ideas how to make ffigen understand bool field?

Answer 1

I was experiencing the same issue, and looking at the output there was a problem with a header file not being found. I added this line to my .bashrc file:

export CPATH="$(clang -v 2>&1 | grep "Selected GCC installation" | rev | cut -d' ' -f1 | rev)/include"

Now the error is gone and booleans are properly generated.

This GitHub issue was useful.

Answer 2

Answer to this issue was to include #include <stdbool.h> in this file. Even though everything worked from C++ code, dart was not aware of bool type.