Use this tag for questions about Dart's Foreign Function Interface (FFI) - the ability to call C directly from Dart. It is equally applicable to applications running in the Dart VM and to Flutter applications (except Flutter Web, of course).
Questions tagged [dart-ffi]
109 questions
4
votes
0 answers
Is there a way to send a dart array to C without copying the array?
I am using dart:ffi.
I have a C function that accepts a pointer to array:
void myCFunc(const void *pointer);
I want to call it from dart, right now, I am calling it like this:
void myDartFunc(Uint8List data) {
final Pointer dataPtr…
HII
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4
votes
1 answer
Dart FFI keep Struct pointer
I am trying to call a C library from dart. The C code as a genertor method such as
a_struc create_struct(void);
and then methods that take in a pointer to struct, such as:
const char *
get_info(const a_struc * s);
I have created the dart binding…
Malcolm
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4
votes
1 answer
Dart ffi - Call Dart From C++
I am making a flutter application where I have my backend as C++. Through dart ffi I am signalling a load call when user enters a certain screen. My problem is Im loading audio in C++ but I want to signal dart that the loading has finished so that I…
cs guy
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4
votes
2 answers
Debug C++ code from Dart package using dart::ffi
I am developing a package in C++ to be used in a Flutter app (and therefore in Dart), using dart::ffi and I was wondering if there was a better way to debug (step by step, variable watch, that sort of things) the C++ code, other than logging…
Facundo Farall
- 500
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4
votes
1 answer
Whats the difference between writing MethodChannel bridge versus dart:ffi bridge to run c/c++ code to get the response?
Before I start my question I want to point out that it's not similar this question.
Difference between writing platform specific code vs dart:ffi code. Here the questioner is asking the actual difference whereas I am trying to know the difference…
Aawaz Gyawali
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3
votes
1 answer
How to convert RGB pixmap to ui.Image in Dart?
Currently I have a Uint8List, formatted like [R,G,B,R,G,B,...] for all the pixels of the image. And of course I have its width and height.
I found decodeImageFromPixels while searching but it only takes RGBA/BGRA format. I converted my pixmap from…
itzMeerkat
- 33
- 5
3
votes
1 answer
Convert Dart String to dartffi Pointer
I used ffigen to generate bindings from a C header file.
One of the methods in C is open(const char *path), and ffigen generated a binding method open(ffi.Pointer path).
If I want to have a dart method open(String path) that access this…
J. Gatica
- 153
- 1
- 10
3
votes
2 answers
How to include dlls in flutter build windows
I am working on a flutter project that runs fine in development.
However I do not know how to get the build to include dll's referenced using FFI.
I can't find clear instructions on how to do it.
I tried following the steps to build an msix here,…
xerotolerant
- 1,955
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3
votes
1 answer
How can I load a C dynamic library for FFI by specifying path in flutter?
I want to load a C Dynamic Library in flutter, how can I specify the path, and open it? is it possible to add .so file to the asset folder?
final dynamicLibrary = DynamicLibrary.open(libraryPath);
final Pointer Function() _someMethod =…
Hamed
- 5,867
- 4
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3
votes
1 answer
What is 'Native Type' for 'char*' in dart FFI?
I have a function like this in C language:
char* getString() {
return "SOME_STRING";
}
now I want to invoke it by FFI in dart, and this is my code:
import 'dart:io';
import 'dart:ffi';
void main(List arguments) {
…
Hamed
- 5,867
- 4
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- 56
3
votes
1 answer
Testing Library functions in a flutter package with Native Functions using Dart::ffi
I am writing a Dart library to access a C shared object using Flutter.
So far, the example app I created is working (somewhat) as expected, but i want to include Unit testing too keep the library somewhat stable.
Details:
Shared Objects are in…
Ryan Deschamps
- 351
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3
votes
0 answers
How to convert C++ cv::Mat to Flutter variable?
I'm very new to flutter. I'm trying to send an image from my OpenCV-C++ code to flutter for iOS device through dart:ffi.
I first converted cv::Mat to vector. I'm not sure if this is a right approach.
Still, I'm stuck at how to define lookup…
fai
- 31
- 1
3
votes
2 answers
Can I call a C++ constructor function in dart ffi?
I'm new to ffi. But I successfully used dart-ffi with functions call.
Now, I'd like to use a C++ object in dart ffi. I don't know if it is possible, but I tried like this.
The prototypes of constructor call are :
function_dart = lib
…
XavierB
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3
votes
1 answer
Casting an int to Uint8 in Dart
I am using the ffi and tyed_data Dart libraries and keep running into an error with this line of code,
Uint8 START_OF_HEADER = 1 as Uint8;
My error:
type 'int' is not a subtype of type 'Uint8' in type cast
What am I doing wrong here? Another…
temp_
- 1,238
- 2
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2
votes
1 answer
Processing flutter images with C++ openCV
I am working on a project, where I want to process my images using C++ OpenCV.
For simplicity's sake, I just want to convert Uint8List to cv::Mat and back.
Following this tutorial, I managed to make a pipeline that doesn't crash the app.…
Oleksandr Firsov
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