HalconVC异常处理

在programmer_guide的pdf文件里面提及到了error_handling

下图是部分异常处理的声明

第一种、面向对象的方法（ Error handling using HException and try/catch）

在C:\Users\Public\Documents\MVTec\HALCON-10.0\examples\cpp\source可以找到example_errorhandling.cpp

• 首先声明

// exception handler

void MyHalconExceptionHandler(const Halcon::HException& except)

{

  throw except;

}

• 然后定义一个函数

Herror TryReadImage(Halcon::HImage &image, const char *filename)

{

  using namespace Halcon;

  Herror  error_num; 

  try

  {

    cout << endl << "Trying to read '" << filename << "' ... ";

    image = HImage::ReadImage(filename); 

  }

  catch (HException &except) 

  {

    error_num = except.err;

    cout << endl << except.message << endl;

    return error_num;

  }

  // success

  cout << "succeeded!" << endl;

  return H_MSG_TRUE;

}

• 注意在调用的过程中首先要exception“句柄”：

 // install the exception handler

  HException::InstallHHandler(&MyHalconExceptionHandler);

• 最后调用TryReadImage

第二种、程序法（不推荐）

在例程(Ctrl+E)——应用范围——一般——搜索“error”有一个dev_set_check的例子如下：

// Local iconic variables 

  Hobject  Image;

  // Local control variables 

  Herror  Error;

  HTuple  WindowHandle, FileName, ReadError;

  if (HDevWindowStack::IsOpen())

    close_window(HDevWindowStack::Pop());

  set_window_attr("background_color","black");

  open_window(0,0,512,512,0,"","",&WindowHandle);

  HDevWindowStack::Push(WindowHandle);

  // Error variable 'Error' activated

  set_check("~give_error");

  FileName = "wrong_name";

  Error = read_image(&Image, FileName);

  ReadError = (int)Error;

  set_check("give_error");

  if (0 != (ReadError!=2))

  {

    Error = write_string(WindowHandle, "wrong file name: "+FileName);

  }

//Now the program will stop with an exception（注意 Error = read_image(&Image, FileName);要在set_check前面才有效。）

  Error = read_image(&Image, FileName);

//Please note that some tuple operations have no return value. Then, the described approach leads to a

memory leak. Please use the object-oriented approach instead.

//请注意，某些元组操作没有返回值。然后，所描述的方法导致一个内存泄漏。请用面向对象的方法来代替。

举一个实时显示图像窗口中鼠标所在位置的像素亮度的例子

read_image (Image, 'fabrik')

while (1)

    dev_set_check ('~give_error')

    try

        dev_display (Image)

        get_mposition (3600, Row, Column, Button)

*在halcon10.0后当鼠标离开图像窗口后，get_mposition算子出现异常。必须要有异常处理才能运行正常！

        get_grayval (Image, Row, Column, Grayval)

        set_tposition (3600, 24, 24)

        write_string (3600, 'Row='+Row)

        set_tposition (3600, 64, 24)

        write_string (3600, 'Column =' +Column)

        set_tposition (3600, 104, 24)

        write_string (3600, 'Grayval =' +Grayval)

    catch (Exception)

        set_tposition (3600, 24, 24)

        write_string (3600, Exception)

    endtry

    dev_set_check ('give_error')

    wait_seconds (0.1)

endwhile

原文链接：http://k594081130.blog.163.com/blog/static/21835901320141217371386/