Qt Snap7 Using Problem

[sierdzio]

Please show us relevant parts of the .cpp file (snap7.cpp, lines 38, 43 etc.).

This error comes from linker and can mean several things:

• you forgot to link a library
• your linked library is corrupted, in wrong architecture, outdated etc.
• general build issue - rebuild the project

[V0rtex]

I want to communucate between qt and siemens plc.


[sierdzio]

Best paste code... screenshots are hard to read.

Anyway, as I said: you need to properly link the library you've got from Siemens. In qmake, this means adding INCLUDEPATH and LIBS to your .pro file. Make sure the library is compiled for the right architecture and using a compatible compiler.

[V0rtex]

QT       += core gui network

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

TARGET = QtSnap7
TEMPLATE = app

DEFINES += QT_DEPRECATED_WARNINGS


DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    

SOURCES += \
        main.cpp \
        mainwindow.cpp \
    snap7.cpp \
    plc_siemens.cpp \
    settings.cpp

HEADERS += \
        mainwindow.h \
    snap7.h \
    plc_siemens.h \
    settings.h \
    global.h

FORMS += \
        mainwindow.ui

TRANSLATIONS = translation/translation_it.ts

include("lib.pri")

RESOURCES += \
    resources.qrc

INCLUDEPATH += $$PWD/.
DEPENDPATH += $$PWD/.

This is my .pro file

LIBS += -L$$PWD/lib/ -lsnap7

INCLUDEPATH += $$PWD/.
DEPENDPATH += $$PWD/.

this is lib .pri file

and These are the contents of the "lib" folder inside the project files

• snap7.dll

• snap7.lib

[SGaist]

Hi and welcome to devnet,

Did you check that your Snap7 is of the correct architecture ? If so, which compiler was used to build it ?

[V0rtex]

@SGaist MinGW 7.3.0 32 Bit

[sierdzio]

Make sure the paths are correct! $$PWD may point to a different location than where project is being built or where the source is.

You can easily print them using:

message($$PWD/lib)

[Christian Ehrlicher]

@V0rtex said in Qt Snap7 Using Problem:

MinGW 7.3.0 32 Bit

Then you won't get any further with snap7.lib I would guess. You should ask the devs for a MinGW import lib (or create them by yourself - should be doable since it's a C only lib).

[V0rtex]

thank you.
https://github.com/abedGNU/QtSnap7 i download the file from here can you check it or try it ?

[SGaist]

Since Snap7 is OpenSource, you should build it with the compiler you are using. That will allow you to get a version that is a bit more recent and avoid the issue you are having currently.

[V0rtex]

@SGaist is there anyway communucate with Siemens Plc in qt library ?

[SGaist]

If by network, then you have the Qt network classes but you will have to implement the protocol yourself.

I think that you should take the time to build Snap7 since it looks like it's already working as you need and maintained.

[V0rtex]

@SGaist i agree with you but i dont know how to do that.
i am not good when things get complicated :)

[mrjj]

@V0rtex
Hi
What about installing the visual studio compiler?
And please don't just install it all
as it eats many gigabytes. You only need the c++ role and SDK.
You have to download it from MS.

I tested with vs 2019 and it just build and ran

[V0rtex]

@mrjj i did it in visual studio It has S7.NET.
I wondered if it could be done with Qt.

[mrjj]

@V0rtex
Hi
This is in Qt i mean.
You can install the visual studio compiler and a Qt that matches this compiler
and use that in Creator 100% like you do with MinGW.
Its just another qt install than the one for mingw.

[V0rtex]

@mrjj thank you it worked .
Happy new year.

[V0rtex]

@mrjj last question what is the different between mingw and msvc ?

[SGaist]

MSVC is from Microsoft (and closed source), MinGW is a port of gcc to Windows.

[mrjj]

Hi
Qt wise. The Qt mingw packet comes with compiler and debugger.
The Qt Visual studio packet is only Qt and compiler and debugger must be downloaded from microsoft.

Visual studio is the standard on Windows, so often its 3rd party libraries come with project files / build instructions for visual studio
and more rarely directly support mingw tool chain.

That said, mingw is a fine compiler works super fine for most.