Configure matlab engine in qtcreator

Zhitoune

Dear all,

I'm facing a problem trying to realize a software in qt that can call matlab function and scripts. But so far I'm miserably failing at setting up my code with matlab libraries and header.
In order to work I need to include 2 header : engine.h and matrix.h
and 2 library : libmx.lib and libeng.lib
so here is my .pro

QT += core gui

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

TARGET = testMatlabEngine
TEMPLATE = app

SOURCES += main.cpp \
        mainwindow.cpp

HEADERS  += mainwindow.h \
            engine.h \
            matrix.h

DISTFILES += \
    codeMatlab.m

win32:LIBS += -Lc:\matlab\r2017a\extern\lib\win64\microsoft -leng
              -LC:\MATLAB\R2017a\extern\lib\win64\microsoft -lmx

INCLUDEPATH += "c:/matlab/r2017b/extern/include"
               "c:/matlab/r2017b/extern/lib/win64/microsoft"

and so far even if the autocompletion of qtCreator recognize matlab function such as "engEvalString" I get the folowing warnings :
warning: Failure to find: engine.h
warning: Failure to find: matrix.h
and the following error
error: cannot find -leng

any idea on how to make it work, I'm running out of idea

edit : I forgot to mention that I'm using window 7

tekojo

Hi @Zhitoune
You are at least missing the \ in the line ends of win32:libs and includepath.
And windows paths need to be in "" so

win32:LIBS += -L"c:\matlab\r2017a\extern\lib\win64\microsoft" -leng \
              -L"c:\MATLAB\R2017a\extern\lib\win64\microsoft" -lmx

and

INCLUDEPATH += "c:/matlab/r2017b/extern/include" \
               "c:/matlab/r2017b/extern/lib/win64/microsoft"

Zhitoune

Thanks @tekojo

unfortunatly, it still does not compile...
I have tried many variations like removing upper case etc etc but so far with no results

Zhitoune

So using :

LIBS += "C:\MATLAB\R2017b\extern\lib\win64\mingw64\libeng.lib" \
        "C:\MATLAB\R2017b\extern\lib\win64\mingw64\libmx.lib"

I somewhtat manage to go to :

error: undefined reference to `engOpen'

(engOpen being a fonction of matlab engine.h ) wich I interpret as : " the headers are fine but it' s a reference to an unknown library".
I checked and I use MinGW 5.3 wich is compatible with my version of matlab

SGaist

Hi,

Aren't you mixing 32 and 64 bit MinGW ?

By the you should rather use forward slashes everywhere. Qt handles the conversion for you. Otherwise use double backslashes.

Zhitoune

Thanks for you help!
that's what I'm trying to determine. I'll post when I know more

Zhitoune

So I checked and it seem that the matlab libraries were compiled using minGW-w64 while I'm using minGW 5.3 32 bit. Can the errors I obtain be the results of this imcompatibility?
So I configured a new kit with MSVC2015 64bit compiler but I get the following error :

mainwindow.obj:-1: error: LNK2019: unresolved external symbol engOpen referenced in function "public: __cdecl MainWindow::MainWindow(class QWidget *)" (??0MainWindow@@QEAA@PEAVQWidget@@@Z)

mrjj

@Zhitoune
Make sure to completely wipe the build folder and
run qmake and rebuild all.

Zhitoune

thanks for your help,

I always use rebuild. should I clean and rebuild?

mrjj

@Zhitoune
well to be 100% sure, please delete the build folder. ( in this case)
This is normally not needed but if anything remains from the minGw compile and u now are using visual studio then odd errors will pop up.
( the .o files should in other folder, but better sure than sorry)

Often rebuild is enough but sometimes full deletion is needed.
Update:
Sorry, i misread.
it complains about engOpen
which i assume is from the MATLAB lib

Zhitoune

yes it is!

mrjj

@Zhitoune
And the MATLAB r2017b libraries are compiled with 2015/2017 64 bit ?

Higher up you show
C:\MATLAB\R2017b\extern\lib\win64\mingw64\libeng.lib"

but maybe it also contains libs for visual studio in other folder than mingw64 ?

Ah yes, seems to be in
c:\matlab\r2017a\extern\lib\win64\microsoft

So those are 2015/2015 compiled?

You cannot fix DLLS from other compilers. It must be same compiler for App and
matlab libs.

So mingw32 wont load 64 bit mingw.

but so we are clear.

You are now using
MSVC2015 compiler (installed by your self)
Qt 2015 version kit
and points to
win32:LIBS += -L"c:\matlab\r2017a\extern\lib\win64\microsoft" -leng
-L"c:\MATLAB\R2017a\extern\lib\win64\microsoft" -lmx

from .pro file?

Zhitoune

So it's finaly working with a kit made of :
Desktop Qt 5.9.2
MSVC2015 64bit

and my .pro file looks like this :

QT += core gui

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

TARGET = testMatlabEngine
TEMPLATE = app

DEFINES += QT_DEPRECATED_WARNINGS

CONFIG += create_prl
CONFIG += link_prl

SOURCES += main.cpp \
           mainwindow.cpp

HEADERS  += mainwindow.h \
            engine.h
            matrix.h

DISTFILES += \
    codeMatlab.m

LIBS += -L"C:/MATLAB/R2017b/extern/lib/win64/microsoft/" -llibeng \
        -L"C:/MATLAB/R2017b/extern/lib/win64/microsoft/" -llibmx

INCLUDEPATH += C:/MATLAB/R2017b/extern/include

Thank you very for your help!!!!

Zhitoune

I also unchecked the "shadow build" in the built settings. it started getting better after that.