how to add library(qmqtt.h) in qmqtt client for windows

[shravani]

hi,

i downloaded code from github for qmqtt client,but im getting error that qmqtt.h not present.
In pro file i added the path correctly.

[raven-worx]

@shravani
You need to be more specific to be able to help, since this can have many causes.
Maybe you just need to rerun qmake to update the makefiles?
Show the directory structure and your .pro file.

[shravani]

hi,
this is my .pro file
and my code is inthis( https://github.com/wuming123057/qmqtt-client) link.
the library i added is https://github.com/emqtt/qmqtt

QT += core gui network

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

CONFIG += c++11
CONFIG+= NO_UNIT_TESTS
TARGET = qmqtt-client
TEMPLATE = app

#NOTICE: add DYLD_LIBRARY_PATH to build environment.
INCLUDEPATH += C:\Qt\qmqtt-master\src
LIBS += -LC:\Qt\qmqtt-master\src -lqmqtt

SOURCES += main.cpp
mainwindow.cpp
connform.cpp
pubform.cpp
subform.cpp

HEADERS += mainwindow.h
connform.h
pubform.h
subform.h
mqttform.h

FORMS += mainwindow.ui
connform.ui
pubform.ui
subform.ui

im getting error:
cannot find -lmqtt
returned 1 exit status

[Fuel]

which name has the library in this path C:\Qt\qmqtt-master\src ?

[raven-worx]

@shravani said in how to add library(qmqtt.h) in qmqtt client for windows:

INCLUDEPATH += C:\Qt\qmqtt-master\src

should point to the sources of qmqtt (specifically where qmqtt.h is placed in)

LIBS += -LC:\Qt\qmqtt-master\src -lqmqtt

Also you need to build qmqtt beforehand. -L should point to the path of the library (.lib) you built

[shravani]

thank you,
i will try building the qmqtt.

[shravani]

@raven-worx
hi,
i tried building the library(i got "could not find executable please specify one" dialog box) there is no .dll or .lib or .so file in build folder.
in build it created 3 folders(.moc,.obj,.pch).could you please tell me how to generate .lib file

[jsulm]

@shravani Can you explain what exactly you did?

[shravani]

@jsulm

from here https://github.com/emqtt/qmqtt i downloaded zip file.in that src/mqtt mqtt.pro i built using qt.but that library not generating any .lib files.
(as u told i need to build qmqtt beforehand. -L should point to the path of the library (.lib) you built.)

[jsulm]

@shravani What I wanted to know was: how exactly did you build? What steps did you execute?
"built using qt" - what does this mean? Qt does not build anything. Do you mean you used QtCreator or qmake?
Can you also post the build log?

[shravani]

@jsulm
i used qt creator.i just opened .pro file (src/mqtt/mqtt.pro from above link)using qtcreator and build all.

[jsulm]

@shravani Can you post the build log?

[shravani]

@jsulm
when i click on build all one dialog box came like below.but in build folder(build-abc-Desktop_Qt_5_8_1_MinGW_32bit-Debug) .lib file not generated only 3 folders(.moc, .obj , .pch) created .!!

[jsulm]

@shravani It looks like you're clicking on Run not on Build. Since mqtt is a lib you cannot execute it. And again: can you post the build log?

[shravani]

@jsulm
sorry ,i can only post what i got after building in build folder.!

[jsulm]

@shravani Why can't you post the build log? You have it in QtCreator. The screen-shots you posted do not help.

[raven-worx]

@shravani
got the folder where you donwloaded qmqtt (where the qmqtt.pro resides) and and execute the following:

1. qmake
2. nmake (for Visual Studio compiler) or mingw32-make (for mingw)

thats it. No QtCreator needed.
Then the .dll and corresponding .lib (MSVC) or .a (mingw32) file will be created in the output folder.

[shravani]

@raven-worx
thank you,
im new to qt could you please tell me how to execute qmake and mingw32-make in windows?

[raven-worx]

@shravani
open a console window and execute "qmake" let it finished and afterwards execute one of the two (the correct one corresponding to your used compiler!) make commands for building.

Make sure that the executable can be found by the system (add the paths to the PATH environment variable)
But those a pretty basics. Probably you should go on reading some learning material first before trying to build a software which is based on a 3rd party library.

[shravani]

@raven-worx
can u give any link to read? and where .lib will be created? in same folder?

[raven-worx]

@shravani
Getting started.
Probably you should consider buying a book about Qt also

[shravani]

@raven-worx
but using qtcreator also, run qmake is possible right?why am i not getting .lib file file?can you see screenshots of my debug folder (above)after building.

[raven-worx]

@shravani
yes, but especially when you are not completley sure what you are doing there are some pitfalls.
You can try to build using QtCreator, but then do not press the Run/Debug button, but the Build button below.

[shravani]

@raven-worx
hi,
after building i came to know qmqtt.lib was created(5th line from last).but i could not find it inorder to add that path to .pro file.can u please tell by default where it will be stored? in build/debug also it is not present(see above post).

thank you

[dheerendra]

Most easiest way is to hit windows search button, search that file and find that directory. Specify this directory in pro file.

[raven-worx]

@shravani
according to this log in the \bin directory.

[shravani]

@raven-worx
thank you very much. now i added that .lib file to .pro file and build all is successful.but as the program start executing im getting this error while debugging.can u please look into it?
i dont understand which dll file is missing and where to add it?

[jsulm]

@shravani How do you start the app? From QtCreator?
On Windows you can use http://www.dependencywalker.com/ to find out which libraries an application needs.
If you want to start your app outside of QtCreator then you first need to deploy it: http://doc.qt.io/qt-5/windows-deployment.html

[shravani]

@jsulm

im running it in qtcreator, not outside.inside qt also do i need to include?

[jsulm]

@shravani In QtCreator it should work. Use http://www.dependencywalker.com to see what is missing.
Besides the lib file - do you have the DLL? Lib file is needed for linking, but DLL is needed at runtime.
Also can you show how you added the lib to pro file?

[shravani]

@jsulm
in this src/ qmqtt.h,.. and .lib files are there.so added that path.

INCLUDEPATH += C:\Qt\qmqtt-master\src
LIBS += -LC:\Qt\qmqtt-master\src -lqmqtt

[jsulm]

@shravani
Again: you need the DLL file to be able to execute your app. Where is qmqtt.dll (or libqmqtt.dll)?

[shravani]

@jsulm
it is inside src only.do i need to add anywhere else again?
after building library it created in /bin so i copied from there to src folder

[jsulm]

@shravani The DLL must be in a directory where the operating system is looking for shared libraries when loading an app. Fastest way is to copy it to the build directory of your app (where your executable is).

[shravani]

This post is deleted!

[shravani]

@jsulm
i added all dlls but now getting this error

[SGaist]

Hi,

You can't start an application like that from explorer, you first have to follow the same steps you would before deploying your application on another computer.

[shravani]

@SGaist
In Qt creator also I'm getting same error after adding ucrtbased.dll to debug folder.
i tried executing examples given in qt but getting same error.
recently i installed this qt 5.8.1 msvc2015 new version because in qt 5.0 it(mqtt) is not working.

[jsulm]

@shravani Which DLLs exactly did you copy and from where? No need to copy ucrtbased.dll when starting from QtCreator.

[shravani]

@jsulm
but while running it showed ucrtbased.dll is missing)DLL not found as above post)