.net - Pointers in Visual C++ Classes -

i updating program written else in c++/cli control variety of different cameras. program uses class control each camera type. class called zyladriver. new c++ , c++/cli, thank in advance , patience.

the sdk camera using has 1 function,at_queuebuffer(), allocate memory read data into. once image has been acquired, at_waitbuffer() can used return pointer acquired data.

i have 2 separate class functions call these functions, zyladriver::expose(), , zyladriver::readimage(uint16 * buffer).

however, running problems memory access going between functions. stands, code below produces system.accessviolationexception when attempt assigned strideless_buffer in zyladriver::readimage().

i believe problem possibly related deficiencies in understanding of how managed memory works in c++/cli. or perhaps more basic deficiencies in understanding of memory management in c++.

zyladriver.h:

#include "driver.h" #include "atcore.h"  ref class zyladriver : driver { public:     zyladriver();     ~zyladriver();     virtual void expose(string^ mode) override;     virtual void readimage(uint16 *buffer, string^ mode) override; protected:     unsigned char* testbufferptr; }; 

zyladriver.cpp

 #include "zyladriver.h"  #include "atcore.h"   using namespace system::windows::forms;  zyladriver::zyladriver(){};  zyladriver::~zyladriver(){};   void zyladriver::expose(string^ mode){      if (mode == "normal){         at_64 imagesizebytes;         at_getint(*pcamera, l"imagesizebytes", &imagesizebytes);         int buffersize = static_cast<int>(imagesizebytes);         //create buffer(s) store acquisition.         testbufferptr = new unsigned char[buffersize];         at_queuebuffer(*pcamera, testbufferptr, buffersize);         at_command(*pcamera, l"acquisitionstart");       }  }   void zyladriver::readimage(uint16 *buffer, string^ mode){      //remove padding @ end of image rows, , handle 16bit deep zyla images.     if (mode == "normal"){         at_64 imagesizebytes;         at_getint(*pcamera, l"imagesizebytes", &imagesizebytes);         int buffersize = static_cast<int>(imagesizebytes);          unsigned char * bufferpointer;         at_waitbuffer(*pcamera, &bufferpointer, &buffersize, at_infinite);          int rows = getrows();         int cols = getcols();         int imagesize = static_cast<int>(imagesizebytes);          at_64 bytesperrow;         at_getint(*pcamera, l"aoistride", &bytesperrow);         int stride_bytes = static_cast<int>(bytesperrow)-2 * rows;         //remove useless data added camera                unsigned char * strideless_buffer = new unsigned char[2 * rows*cols];         (int y = 0; y < rows; y++){             (int x = 0; x < 2 * cols; x++){                 strideless_buffer[x + y * 2 * cols] = bufferpointer[x + y*bytesperrow];             }         }         //converting array of 1-byte data 2-byte pixels.         uint16* imagebuffer_int = new uint16[rows*cols];         memcpy(imagebuffer_int, strideless_buffer, 2 * rows*cols);         //simplicio assumes row counting starts @ top, andor software assumes         //it starts @ bottom. need flip image here consistancy.         (int y = 0; y < rows; y++){             (int x = 0; x < cols; x++){                 buffer[x + y*cols] = imagebuffer_int[x + (rows - y - 1)*cols];             }         }         delete[] strideless_buffer;         delete[] imagebuffer_int; 

please let me know if can clarify or add information.

i can create class member pointer (which tried first), can moved around gc. at_queuebuffer doesn't know that. when try access buffer class function, find uninitialized memory. second attempt use pin_ptr, these cannot class members.

that regarding piece of code:

//create buffer store acquired data. unsigned char * userbuffer = new unsigned char[buffersize]; 

now i'm not sure how picture c++/cli work, that's unmanaged block of memory. never "move around". not "deallocated after expose() finishes".

i don't doubt may have problem, analysis wrong. perhaps post actual working example demonstrates instead of trying guess is.