mex file and gpib link

Question

Vlad 2014-6-11

0
链接

此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/133742-mex-file-and-gpib-link

回答： Dekun Pei 2014-6-16

    Hello everyone.
  I have the following question. I adjust some device via gpib-connection. In main m-file I write:
    glink=gpib('ni', 0 , 1);
Can I call my mex-file with glink parameter: myMex(glink)? I mean, there is a string somewhere in mex-file:
    fopen(glink);
    fprintf(glink, '*IDN?');
    fscanf(glink);
    fclose(glink);

And how can I check glink is an object? Does the 'mxIsObject' exist?

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

请先登录，再回答此问题。

Answer 1

James Tursa 2014-6-11

2
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/133742-mex-file-and-gpib-link#answer_140464

在 MATLAB Online 中打开

To examine what the class name is for a variable in a mex routine you can use mxGetClassName:

http://www.mathworks.com/help/matlab/apiref/mxgetclassname.html

E.g.,

char *classname;
classname = mxGetClassName(prhs[0]);

Then you can test classname against any particular string (e.g., "glink") to see if it is an object of that class.

0 个评论
显示 -2更早的评论隐藏 -2更早的评论

请先登录，再进行评论。

Answer 2

Dekun Pei 2014-6-16

0
链接

此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/133742-mex-file-and-gpib-link#answer_141200

In addition to what James said, I would be careful with using "fopen", "fprintf", "fscanf" and "fclose" in your mex file. These functions in MATLAB are overloaded to support instrument objects. However, this is NOT the case in mex file as the C/C++ version of these function will be used and they are most definitely not set up to handle MATLAB objects.

If you must use them on glink in a C/C++ mex file, call them through "mexCallMATLAB" (<http://www.mathworks.com/help/matlab/apiref/mexcallmatlab.html)>, which essentially calls these function in MATLAB.