This is the code inside my .so file.
RustGreetings g = new RustGreetings();
String r ;
try{
**r = g.sayHello("world");**
Log.d("tests","----------------"+r);
} catch (Exception ex){
Log.e("JNI","--------"+ex.getMessage());
}
I want to call this function, that is available inside my precompiled .so file. But when I call this function it shows the error below:
Invalid argument(s): Failed to lookup symbol 'g.sayHello': undefined symbol: g.sayHello
This is my lookup function
typedef HelloWorld = Pointer<Utf8> Function();
typedef HelloWorldDart = Pointer<Utf8> Function();
late HelloWorldDart _helloWorldDart;
final device = Platform.isAndroid
? DynamicLibrary.open(libGreetings)
: DynamicLibrary.process();
_helloWorldDart =
device.lookupFunction<HelloWorld, HelloWorldDart>('g.sayHello');
Related
public var O_RDONLY: Int32 { get }
When I'm looking at stuff inside Darwin.sys.* or Darwin.POSIX.* for example, a lot of these constants are defined as getters. But how does one see the actual value without evaluating the code?
public var O_RDONLY: Int32 { get }
is what the Swift importer generates from the macro definition
#define O_RDONLY 0x0000 /* open for reading only */
in the <sys/fcntl.h> include file. Although this is a fixed value, known at compile time, the Swift importer does not show the value in the generated Swift interface.
Note also that a macro definition in a C header file may depend on other macros, and on other “variables” such as compiler flags, the processor architecture, etc.
I am not aware of a way to navigate to that C definition from a Swift file, or any other way to show the defined value in a pure Swift project. As a workaround, one can
add a C file to the project,
use the macro in some C function, and
“jump to definition” from there.
I ended up with the following solution:
const fs = require('fs');
const { exec } = require("child_process");
const getterRegEx = /^(.*)public var (.+): (.+) { get }(.*)$/;
const code = String(fs.readFileSync('./generatedSwift.swift'));
const lines = code.split('\n').map((line, i) => {
const arr = getterRegEx.exec(line);
if (arr) {
const [all, prefix, constant, type, suffix] = arr;
return `print("let ${constant}: ${type} = ", ${constant}, separator: "")`;
}
return `print("""\n${line}\n""")`;
});
lines.unshift('import Foundation');
fs.writeFileSync('./regeneratedSwift.swift', lines.join('\n'));
exec('swift ./regeneratedSwift.swift', (err, stdout, stderr) => {
if (err) {
console.error(`exec error: ${err}`);
return;
}
if (stderr) {
console.log(`stderr: ${stderr}`);
return;
}
console.log(`stdout: ${stdout}`);
});
Copy definitions generated by the XCode and save into a file named generatedSwift.swift the run node index.js in the same folder.
The output will contain the Swift code where all
public var Constant: Type { get }
are replaced with
let Constant = Value
and all other lines will remain the same.
I am having trouble reading a string (file name : 'aFile.csv') from SFunction parameter. The error I get doesn't make sense to me
I am using MSVC++(2017).
The error appears to come from ssGetSFcParam inside mxGetString
Here is a snippet of the code that has the proble (in the mdlStart method)
static void mdlStart(SimStruct *S)
{
FILE* fp;
char buffer[255];
char* fileStr;
char* paramStr;
int_T fstatus;
int_T pstatus;
const int_T flen = (int_T)mxGetN((ssGetSFcnParam(S, 0)))*sizeof(char)+1;
const int_T plen = (int_T)mxGetN((ssGetSFcnParam(S, 1)))*sizeof(char)+1;
fileStr = mxMalloc(flen);
paramStr = mxMalloc(plen);
fstatus = mxGetString((ssGetSFcParam(S,0)),fileStr,flen);
pstatus = mxGetString((ssGetSFcParam(S,1)),paramStr,plen);
real_T* Defval = (real_T *)mxGetData(PARAM_DEF2(S));
fp = fopen(fileStr, "r");
// additional code here, but has nothing to do with the error
mxFree(flen);
mxFree(plen);
fclose(fp);
}
Error using mex
Creating library FileReader.lib and object FileReader.exp
FileReader.obj : error LNK2019: unresolved external symbol
ssGetSFcParam referenced in function mdlStart FileReader.mexw64 :
fatal error LNK1120: 1 unresolved externals
The error message says everything: there is no S-function method called ssGetSFcParam. You need to use ssGetSFcnParam, which you have used twice, and then also made a typo twice.
So, I was trying to read a file from GCS line-by-line to append line numbers at the end of the line and later make a PCollection out of it(Basically, the goal is to index a PCollection). Hence I've written this code but gives errors:
Below is the implementation classes of FileBasedSource and FileBasedReader:
private static class LineSource extends FileBasedSource<String> {
public LineSource(String fileOrPattern) {
super(fileOrPattern);
}
private static class LineReader extends FileBasedSource.FileBasedReader<String> {
public LineReader(LineSource source) {
super(source);
}
}
Code I wrote which uses these classes to read file line by line is:
try {
LineSource<String> f = new LineSource(fileName);
LineReader<String> b = new LineReader(f);
b.startReading(channel);
int index = 0;
while(b.readNextRecord()){
LOG.info("FileBasedSource: "+b.getCurrent());
c.output(b.getCurrent()+","+index);
index++;
}
b.close();
} catch (IOException e) {
e.printStackTrace();
}
But i get these errors:
java:[115,49] ')' expected
[ERROR] flatFileTest.java:[115,57] illegal start of expression
[ERROR] flatFileTest.java:[175,2] reached end of file while parsing
I guess startReading() method should be implemented again maybe.
I'm relatively new to Dataflow. Can you please help on this?
What I wish is to catch the keypress using JScript .NET, and compile the code using that jsc.exe.
So, is there any equivalent of "addEventListener("keyDown", keyCheck)" from FLASH actionscript. Or GetAsyncKeyState() from C++.
And what library do I have to use?
Please be kind enough to share a small, simple example.
Here's a simple solution if you're writing a console app.
import System;
Console.Write("Press the M key... ");
var key:ConsoleKeyInfo;
while (1) {
while (!Console.KeyAvailable) {
System.Threading.Thread.Sleep(1);
}
key = Console.ReadKey(1);
if (key.Key == ConsoleKey.M) break;
}
Console.Write("Accepted.");
Read more about ConsoleKeyInfo.
If you need GetAsyncKeyState(), it is possible to access the method in JScript.NET. A couple days ago I came across a JScript.NET function that exposes Win32 API methods via P/Invoke. Here it is, slightly modified for simpler syntax (allowing pass-through of arguments from API function definitions).
import System;
import System.Reflection;
import System.Reflection.Emit;
// Invoke a Win32 P/Invoke call.
// credit: http://cx20.main.jp/blog/hello/2013/03/07/hello-win32-api-jscript-net-world/
function InvokeWin32(dllName:String, returnType:Type, methodName:String, params:Object[]) {
var paramTypes:Type[] = new Type[params.length];
for (var i:int in params) {
paramTypes[i] = params[i].GetType();
}
// Begin to build the dynamic assembly
var domain = AppDomain.CurrentDomain;
var name = new System.Reflection.AssemblyName('PInvokeAssembly');
var assembly = domain.DefineDynamicAssembly(name, AssemblyBuilderAccess.Run);
var module = assembly.DefineDynamicModule('PInvokeModule');
var type = module.DefineType('PInvokeType',TypeAttributes.Public
+ TypeAttributes.BeforeFieldInit);
// Define the actual P/Invoke method
var method = type.DefineMethod(methodName, MethodAttributes.Public
+ MethodAttributes.HideBySig + MethodAttributes.Static +
MethodAttributes.PinvokeImpl, returnType, paramTypes);
// Apply the P/Invoke constructor
var ctor = System.Runtime.InteropServices.DllImportAttribute.GetConstructor(
[System.String]
);
var attr = new System.Reflection.Emit.CustomAttributeBuilder(ctor, [dllName]);
method.SetCustomAttribute(attr);
// Create the temporary type, and invoke the method.
var realType = type.CreateType();
return realType.InvokeMember(methodName, BindingFlags.Public + BindingFlags.Static
+ BindingFlags.InvokeMethod, null, null, params);
}
With this function, you can expose Win32 DLL methods with the following syntax. (See? Told you it was simpler.)
// ShowWindowAsync(hWnd:IntPtr, nCmdShow:int);
function ShowWindowAsync(... args:Object[]):boolean {
return InvokeWin32("user32.dll", System.Boolean, "ShowWindowAsync", args);
}
// GetWindowLong(hWnd:IntPtr, nIndex:int);
function GetWindowLong(... args:Object[]):int {
return InvokeWin32("user32.dll", System.Int32, "GetWindowLong", args);
}
// FindWindowEx(parentHandle:IntPtr, childAfter:IntPtr,
// lclassName:IntPtr, windowTitle:String);
function FindWindowEx(... args:Object[]):IntPtr {
return InvokeWin32("user32.dll", System.IntPtr, "FindWindowEx", args);
}
And I've never used GetAsyncKeyState(); but since it's a user32.dll method, I'm guessing it'll work the same way. (Edit: It does.)
// GetAsyncKeyState(vKey:int);
function GetAsyncKeyState(... args:Object[]):short {
return InvokeWin32("user32.dll", System.Int16, "GetAsyncKeyState", args);
}
Then for a trivial example:
import System; // for Console methods
import System.Windows.Forms; // for Keys object constants
Console.Write("Press the M key... ");
// while the M key is not being pressed, sleep
while (!GetAsyncKeyState(Keys.M)) {
System.Threading.Thread.Sleep(1);
}
// flush input buffer
while (Console.KeyAvailable) Console.ReadKey(1);
Console.WriteLine("Accepted.");
I'm trying to call a dll function in matlab. I have a C++ struct as shown in sixense.h:
typedef struct _sixenseControllerData {
float pos[3];
float rot_mat[3][3];
float joystick_x;
float joystick_y;
float trigger;
...
} sixenseControllerData;
and functions I could call:
SIXENSE_EXPORT int sixenseInit( void );
SIXENSE_EXPORT int sixenseGetAllNewestData( sixenseAllControllerData * );
I can easily get this to work with calllib('sixense','sixenseInit') since there is no input, but for the function sixenseGetAllNewestData I need to have a struct pointer. I realize that libstruct is what I need to use. However, I don't seem to be doing it right.
So I tried libstruct like so:
libstruct('sixenseControllerData')
and I get the error:
??? Error using ==> feval
Undefined function or variable 'lib.sixenseControllerData'.
Error in ==> libstruct at 15
ptr=feval(['lib.' structtype]);
EDIT: here is my current unedited proto file:
http://pastebin.com/PemmmMqF
the full header file is available here:
https://github.com/rll/sixense/blob/master/include/sixense.h
For C structures, loadlibrary generates types named: s_{NAME} where {NAME} is the name of the structure. In your case we create a pointer as:
s = libstruct('s_sixenseControllerData');
We can see this fact by instructing MATLAB to generate a prototype file:
>> loadlibrary('sixense', 'sixense.h', 'proto','sixense_proto')
A prototype file is a file of MATLAB commands which we can modify and use in place of a header file. In this case, the file will contain something like:
sixense_proto.m
...
structs.s_sixenseControllerData.members = struct('pos', 'single#3', 'rot_mat', 'single#9', 'joystick_x', 'single', 'joystick_y', 'single', 'trigger', 'single', 'buttons', 'uint32', 'sequence_number', 'uint8', 'rot_quat', 'single#4', 'firmware_revision', 'uint16', 'hardware_revision', 'uint16', 'packet_type', 'uint16', 'magnetic_frequency', 'uint16', 'enabled', 'int32', 'controller_index', 'int32', 'is_docked', 'uint8', 'which_hand', 'uint8', 'hemi_tracking_enabled', 'uint8');
structs.s_sixenseAllControllerData.members = struct('controllers', 's_sixenseControllerData#4');
....
Unfortunately, a limitation of loadlibrary is that it does not support nested structure very well, especially if a structure contains a pointer to another structure (or an array in this case):
Nested structures or structures containing a pointer to a structure are
not supported. However, MATLAB can access an array of
structures created in an external library.
So you will not be able to directly create the sixenseAllControllerData structure on the MATLAB side, which is defined in the C header file as:
typedef struct _sixenseAllControllerData {
sixenseControllerData controllers[4];
} sixenseAllControllerData;
According to the following discussion, one workaround is to "unroll"/"flatten" the array into separate variables. You can either do this in a copy of the header file, or making the changes in the generated prototype file (which I think is the preferred way). You can do this without having to recompile the shared library.
In your case, change the nested structure in the generated sixense_proto.m file into:
structs.s_sixenseAllControllerData.members = struct(...
'controllers1', 's_sixenseControllerData', ...
'controllers2', 's_sixenseControllerData', ...
'controllers3', 's_sixenseControllerData', ...
'controllers4', 's_sixenseControllerData');
Now we can create a pointer to this structure, and call the C method:
s = libstruct('s_sixenseAllControllerData');
s.controllers1 = libstruct('s_sixenseControllerData');
s.controllers2 = libstruct('s_sixenseControllerData');
s.controllers3 = libstruct('s_sixenseControllerData');
s.controllers4 = libstruct('s_sixenseControllerData');
out = calllib('sixense', 'sixenseGetAllNewestData', s);
get(s)
A completely different solution is to write a MEX-function to interface with the library. It is just like any other C/C++ code, only using mxArray and the MX-API to interface with MATLAB...
Example:
To test the above, I created a simple DLL with similar structures, and implemented the above solution. Here is the code if someone wants to test it:
helper.h
#ifndef HELPER_H
#define HELPER_H
#ifdef _WIN32
#ifdef EXPORT_FCNS
#define EXPORTED_FUNCTION __declspec(dllexport)
#else
#define EXPORTED_FUNCTION __declspec(dllimport)
#endif
#else
#define EXPORTED_FUNCTION
#endif
#endif
mylib.h
#ifndef MYLIB_H
#define MYLIB_H
#include "helper.h"
typedef struct _mystruct {
int pos[3];
double value;
} mystruct;
typedef struct _mystruct2 {
mystruct arr[2];
int num;
} mystruct2;
EXPORTED_FUNCTION void myfunc(mystruct *);
EXPORTED_FUNCTION void myfunc2(mystruct2 *);
#endif
mylib.c
#define EXPORT_FCNS
#include "helper.h"
#include "mylib.h"
void myfunc(mystruct *s)
{
s->pos[0] = 10;
s->pos[1] = 20;
s->pos[2] = 30;
s->value = 4.0;
}
void myfunc2(mystruct2 *s)
{
int i;
for(i=0; i<2; i++) {
myfunc(&(s->arr[i]));
}
s->num = 99;
}
After compiling the above into a DLL, we generate the initial prototype file:
loadlibrary('./mylib.dll', './mylib.h', 'mfilename','mylib_proto')
unloadlibrary mylib
I edit the prototype file as described before:
function [methodinfo,structs,enuminfo,ThunkLibName] = mylib_proto()
MfilePath = fileparts(mfilename('fullpath'));
ThunkLibName = fullfile(MfilePath,'mylib_thunk_pcwin64');
enuminfo = [];
structs = [];
structs.s_mystruct.members = struct('pos','int32#3', 'value','double');
structs.s_mystruct2.members = struct('arr1','s_mystruct', ...
'arr2','s_mystruct', 'num','int32');
ival = {cell(1,0)};
methodinfo = struct('name',ival, 'calltype',ival, 'LHS',ival, ...
'RHS',ival, 'alias',ival, 'thunkname',ival);
methodinfo.thunkname{1} = 'voidvoidPtrThunk';
methodinfo.name{1} = 'myfunc';
methodinfo.calltype{1} = 'Thunk';
methodinfo.LHS{1} = [];
methodinfo.RHS{1} = {'s_mystructPtr'};
methodinfo.thunkname{2} = 'voidvoidPtrThunk';
methodinfo.name{2} = 'myfunc2';
methodinfo.calltype{2} = 'Thunk';
methodinfo.LHS{2} = [];
methodinfo.RHS{2} = {'s_mystruct2Ptr'};
end
Now we can finally invoke functions exposed by the DLL:
%// load library using proto file
loadlibrary('./mylib.dll', #mylib_proto)
%// call first function with pointer to struct
s = struct('pos',[0,0,0], 'value',0);
ss = libstruct('s_mystruct',s);
calllib('mylib', 'myfunc', ss)
get(ss)
%// call second function with pointer to struct containing array of struct
xx = libstruct('s_mystruct2');
xx.arr1 = libstruct('s_mystruct');
xx.arr2 = libstruct('s_mystruct');
calllib('mylib', 'myfunc2', xx)
get(xx)
%// clear references and unload library
clear ss xx
unloadlibrary mylib