API changes in R2019a?
显示 更早的评论
I have a (Win64) C# software package allowing users to transfer data to MATLAB for user defined processing through a MATLAB script and transfer back the results.
It relies on the MATLAB API with libeng.dll etc, and was working fine with R2018b, but has stopped working with R2019a. I changed nothing, so assume something changed with the MATLAB API, but can find no mention of such a change here or on the 'News' pages.
Any bright ideas?
1 个评论
James Tursa
2019-7-30
Did you recompile it with R2019a, or are you using the previously compiled code?
回答（1 个）
James Tursa
2019-7-30
0 个投票
I don't know if this is the cause of your problems, but there was a change to the low level mxArray variable structure in R2019a. So code might have to be recompiled in order to work.
5 个评论
Bo
2019-7-31
Bruno Luong
2019-7-31
James, what is the low-level change of mxArray? I did not notice and my old mex files are still working without recompile them.
James Tursa
2019-7-31
编辑：James Tursa
2019-7-31
Documented in my mex MATLAB API version FEX submission here (in the header file):
And here is the low level change for R2019a:
* R2019a - First version where the CrossLink field in the mxArray header
* has been moved next to the reverse CrossLink field. I.e.,
* R2018b-:
* mxArray *RevCrossLink;
* mxClassID ClassID;
* int VariableType;
* mxArray *CrossLink;
* :
* etc.
* R2019a+:
* mxArray *RevCrossLink;
* mxArray *CrossLink;
* mxClassID ClassID;
* int VariableType;
* :
* etc.
If you are only calling API functions that deal with this in the background then I can easily see that this may not affect your mex routines.
Bruno Luong
2019-7-31
OK so they change the order of the fields. I can't see the motivation. The aligment is more or less identical for 64-bit pointer (all MATLAB) no?
That looks odd.
James Tursa
2019-7-31
Since ClassID and VariableType are both ints they occupy 4 bytes each. Having them next to each other means they won't mess up any 8-byte boundary alignments for the stuff around them. So, yes, I agree that the compiler won't need to add any padding in either the old or the new definitions to maintain 8-byte boundary alignments of the nearby fields.
Motivation for the change? I suppose the new definition looks nicer having the crosslink stuff next to each other. But I suspect the real motivation is just to irritate me and mess up my mex hacking code ...
类别
在 帮助中心 和 File Exchange 中查找有关 C Matrix API 的更多信息
产品
2019-7-31
Community Treasure Hunt
Find the treasures in MATLAB Central and discover how the community can help you!
Start Hunting!
Translated by 
