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');
so I have been trying to create 3 'accelstepper' objects.
This is a screenshot of my code in case the code section doesn't appear. Also, this is a screenshot of the file "stepper_directory.h"
#include <mbed.h>
#include "stepper_directory.h"
//Include accelstepper library
#include <AccelStepper.h>
//Create accelstepper object for the Z-Axis actuator
AccelStepper zaxis(uint8_t interface = AccelStepper::DRIVER, uint8_t zstep = ZSTEP, uint8_t zdir = ZDIR);
//Create accelstepper object for the theta axis actuator
AccelStepper taxis(uint8_t interface = AccelStepper::DRIVER, uint8_t tstep = TSTEP, uint8_t tdir = TDIR);
//Create accelstepper object for the magnet actuator
AccelStepper maxis(uint8_t interface = AccelStepper::DRIVER, uint8_t mstep = MSTEP, uint8_t mdir = MDIR);
This is the header file i've used "stepper_directory.h"
#ifndef _STEPPER_DIRECTORY
#define _STEPPER_DIRECTORY
#include "PinNames.h"
//Pin Definitions
#define ZSTEP PA_7
#define ZDIR PA_0
#define TSTEP PA_8
#define TDIR PA_1
#define MSTEP PA_9
#define MDIR PA_2
I've tried to setup one stepper in my main code in main.cpp as follows:
int main() {
// put your setup code here, to run once:
zaxis.setMaxSpeed(188000);
while(1) {
// put your main code here, to run repeatedly:
}
}
But the platformIO compiler is throwing out this lines:
src\main.cpp: In function 'int main()':
src\main.cpp:17:7: error: request for member 'setMaxSpeed' in 'zaxis', which is of non-class type 'AccelStepper(uint8_t, uint8_t, uint8_t)
{aka AccelStepper(unsigned char, unsigned char, unsigned char)}'
zaxis.setMaxSpeed(188000);
^~~~~~~~~~~
*** [.pio\build\nucleo_f410rb\src\main.o] Error 1
I have been attempting to search for what is wrong with my object instantiations to no avail. I would really appreciate if there someone could explain what is wrong with this. This is a screenshot of the error in question
The problem is here.
//Create accelstepper object for the Z-Axis actuator
AccelStepper zaxis(uint8_t interface = AccelStepper::DRIVER, uint8_t zstep = ZSTEP, uint8_t zdir = ZDIR);
This is a function declaration. It takes three arguments and returns AccelStepper. You cannot initialize an instance of AccelStepper with this line of code.
I assume AccelStepper's constructor is something like this:
AccelStepper AccelStepper(uint8_t interface, uint8_t zstep, uint8_t zdir);
You can initialize your instance this way:
AccelStepper zaxis(AccelStepper::DRIVER, ZSTEP, ZDIR);
I get the following error
In function w_Endline:
/home/prog2/in_out.c:113:19: error: assignment of read-only l ocation ‘*(sent + (sizetype)(endlen * 1ul))’
sent[endlen]='\0';
/home/prog2/in_out.c: In function ‘w_White’:
/home/prog2/in_out.c:119:19: warning: initialization discards ‘const’ qualifier from pointer target type
char* endlen=sent+whitelen;
/home/prog2/in_out.c:120:6: warning: implicit declaration of function ‘isspace’ [-Wimplicit-function-declaration]
while(endlen>sent &&isspace(*endlen))
FILES
1.in_out.c http://ideone.com/nI15F4
void w_Endline(const char* sent)
{
size_t endlen=strlen(sent)-1;
if(sent[endlen]=='\n')
sent[endlen]='\0';
}
void w_White(const char* sent)
{
size_t whitelen=strlen(sent);
char* endlen=sent+whitelen;
while(endlen>sent &&isspace(*endlen))
{
endlen='\0';
--endlen;
}
}
2.in_out.h http://ideone.com/lDxxhY
Dont use const in w_Endline if you are modifying the pointer also you need ctype.h header for isspace() function. Also in w_White function if you are assigning a const pointer the pointer also needs to be const.
char* endlen=sent+whitelen;
should be
const char* endlen=sent+whitelen;// because sent is const
Actually const qualifier means read-only
I have a module defined in my C code like so:
static struct PyModuleDef module_def = {
PyModuleDef_HEAD_INIT,
"the_module_name", /* m_name */
module_documentation, /* m_doc */
//....
};
and a function to initialize it:
PyMODINIT_FUNC init_the_module(void)
{
PyObject *mod, *submodule;
PyObject *sys_modules = PyThreadState_GET()->interp->modules;
mod = PyModule_Create(&module_def);
PyModule_AddObject(mod, "some_submodule", (submodule = init_the_submodule()));
PyDict_SetItemString(sys_modules, PyModule_GetName(submodule), submodule);
Py_INCREF(submodule);
// more submodules..
return mod;
}
The application that I am embedding python into is quite big and I can not change the workflow much. At this point Py_Initialize has already been called, so I can not call PyImport_ExtendInittabor PyImport_AppendInittab .
How can I create and add the module to the system modules?
Maybe I can manipulate the modules dictionary directly? Like so:
PyObject *modules, *the_module;
modules = PyImport_GetModuleDict();
PyDict_SetItemString(modules, "the_module_name", init_the_module());
the_module = PyDict_GetItemString(modules, "the_module_name"); //this is getting something back
std::cout << PyDict_Size(the_module) << std::endl; // this prints -1
The easiest way to handle this is to statically initialize your statically-linked modules by directly calling initspam() after the call to Py_Initialize() or PyMac_Initialize():
int main(int argc, char **argv)
{
/* Pass argv[0] to the Python interpreter */
Py_SetProgramName(argv[0]);
/* Initialize the Python interpreter. Required. */
Py_Initialize();
/* Add a static module */
initspam();
An example may be found in the file Demo/embed/demo.c in the Python source distribution.
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