How to correctly manage DLLs on Matlab path

Question

Nikita Visnevski 2019-7-17

0
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此问题的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/472240-how-to-correctly-manage-dlls-on-matlab-path

编辑： Nikita Visnevski 2019-10-23

On Windows, I am building a mex function "myFcn_mex" which links to a DLL "myLib.dll" via an import library "myLib.lib". I have the following directory structure:

%MY_PROJECT_BASE%\bin\win\x86_64

myLib.dll

myLib.lib

%MY_PROJECT_BASE%\src\include

myLib.h

%MY_PROJECT%\src\matlab

myFcn.m

My Matlab code looks as follows:

function myFcn
    if ~coder.target('MATLAB')
        projectBase = getenv('MY_PROJECT_BASE');
        includePath = [projectBase filesep 'src' filesep 'include'];
        libPath     = [projectBase filesep 'bin' filesep 'win' filesep 'x86_64'];
        libName     = 'myLib.lib';
        coder.ceval('myFcn');
        coder.cinclude('myLib.h');
        coder.updateBuildInfo('addIncludePaths',includePath);
        coder.updateBuildInfo('addLinkObjects',libName,libPath,'',true,true);
    else
        myFcn_mex;
    end
end

In Matlab I do this:

[Line 1] >> addpath([getenv('MY_PROJECT_BASE') filesep 'bin' filesep 'win' filesep 'x86_64']);
[Line 2] >> cd(getenv('MY_PROJECT'));
[Line 3] >> codegen myFcn
[Line 4] >> myFcn

So:

DLL and LIB files live in a folder which has been succesfully added to Matlab path [Line 1]
Folder where dll and lib files reside is not the same where I need to create my mex function [Line 2]
Codegen command successfully runs and creates the file myFcn_mex.mexw64 in my working directory [Line 3]
Calling the mex function [Line 4] results in error:

...
Missing dependent shared libraries:
'myLib.dll' required by
...

The function call suceeds if I copy the DLL locally:

>> !cp %MY_PROJECT_BASE%\bin\win\x86_64\myLib.dll .\

I quite clearly remember that in the past just adding the directory where dll file resides to the Matlab path used to work. It no longer seems to be the case. I either have to have this DLL in my current directory or on the OS path, which would require me to exit Matlab, change the OS Path environmant variable, and then restart Matlab.

Questions:

Is there not another way of managing a DLL? I do not want to do either of the two options I described above.
How different would be the way to do that with a myLib.so file on Linux or myLib.dylib on Mac?

Thanks in advance

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Answer 1

Prashant Nirmal 2019-10-23

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https://ww2.mathworks.cn/matlabcentral/answers/472240-how-to-correctly-manage-dlls-on-matlab-path#answer_397787

编辑：Prashant Nirmal 2019-10-23

As mentioned in this link you must have dll file either on system path or in the same folder.

In case of Linux and Mac. See "-L" and "-l" flags in "mex" documentation

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Answer 2

Nikita Visnevski 2019-10-23

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此回答的直接链接

https://ww2.mathworks.cn/matlabcentral/answers/472240-how-to-correctly-manage-dlls-on-matlab-path#answer_397880

编辑：Nikita Visnevski 2019-10-23

Well, mex function itself is essentially a kind of a dll (or so/dylib, depending on the platform), yet I do not have to have mex files on system path or current directory. There is something that Matlab is doing to manage mex files more robustly than any generic dll. I guess it is what it is. I was just hoping there would be a better way.

Thanks