Taglib Library

[raven-worx]

@lucas_1603
what compiler are you using?
anyway you never link against DLL file. And there should also be a corresponding warning in the build console
LIBS += -L$$PWD/taglib -ltag or LIBS += -L$$PWD/taglib -llibtag (depnding how the lib file is called)
taglib should also provide a .lib/.a file?

[Lucas_1603]

@raven-worx
I'm using MinGW compiler. Taglib provides a .dll and a .a file

[jsulm]

@lucas_1603 Did you build the lib by yourself?
If you downloaded it: from where and which compiler was used to build it?

[Lucas_1603]

@jsulm I downloaded taglib from taglib.org and used cmake to build it. After successfully built, I got a .dll and a .dll.a file. What I have to do next to link taglib to my project? I'm new in Qt so guide me step-by-step, please.
Thanks a lot

[jsulm]

@lucas_1603 There should be a .lib file as well as @raven-worx said.
Also, the way you use LIBS in pro file is wrong: remove .dll from file name (again, like @raven-worx suggested). When adding libs using -l the "lib" prefix and file extension (.lib, .so, ...) must be removed. Example: if lib is called libfoo.lib you add "-lfoo" to your pro file.

[Lucas_1603]

@jsulm I actually cannot find any .lib files. I built taglib following the guidelines of this tutorial. After building process completed, it just generated 2 files more, one is .dll and the other is .dll.a as I said before. I don't know whether I built taglib right or wrong, or there were something I don't well aware of :((

[jsulm]

@lucas_1603 Then fix LIBS in your pro file as described before and try again.

[Lucas_1603]

@jsulm I tried to fix it to LIBS += -L$$PWD/taglib -ltag as you suggested but it raised "cannot find -ltag" error!

[jsulm]

@lucas_1603 What is the exact file name of the lib?
Also, $$PWD/taglib is a relative path - are you sure it is correct (you can check the linker output to see what exactly is passed to -L.

[Lucas_1603]

@jsulm I would like to describe more details for you to understand my problems clearly

---

This is exactly what I have tried :

After downloading taglib (version 1.11.1) from taglib.org, I built it with cmake and got a .dll and a .dll.a file. Then I brought taglib folder to where my Qt project folder is in and named it 'myTaglib' as this picture

When I go to 'myTaglib' folder, I'll get these items

Now jumping into .pro file, I tried to link to taglib:

QT += quick multimedia core
CONFIG += c++11
INCLUDEPATH += $$PWD/myTaglib
DEPENDPATH += $$PWD/myTaglib
LIBS += -L$$PWD/myTaglib -ltag

And in header file, I included necessary files and using namespace TagLib like this:

#include <tag.h>
#include <fileref.h>
#include <mpeg/id3v2/id3v2tag.h>
#include <mpeg/mpegfile.h>
#include <mpeg/id3v2/id3v2frame.h>
#include <mpeg/id3v2/id3v2header.h>
#include <mpeg/id3v2/frames/attachedpictureframe.h>
using namespace TagLib;

After all, I built my project and got some errors:

...
undefined reference to `__imp__ZN6TagLib8FileNameC1EPKc' in player.cpp - line 94
undefined reference to `__imp__ZN6TagLib7FileRefC1ENS_8FileNameEbNS_15AudioProperties9ReadStyleE' in player.cpp - line 94
undefined reference to `__imp__ZNK6TagLib7FileRef3tagEv' in player.cpp - line 95
undefined reference to `__imp__ZNK6TagLib6String10toCWStringEv' in player.cpp - line 97
undefined reference to `__imp__ZNK6TagLib6String10toCWStringEv' in player.cpp - line 96
...

Then, I checked these lines but it didn't show something like underlined error or red text or something like that, you can see this picture

[jsulm]

@lucas_1603 Can you show the linker call? Either it can't find the lib or the lib is not compatible.

[Lucas_1603]

@jsulm You mean this one (sorry if I misunderstood what you mean):

[jsulm]

@lucas_1603 Yes, your taglib is not compatible with the compiler you're using.
Do you really use exact same compiler you used to compile taglib?

[Lucas_1603]

@jsulm I built taglib with MinGW and in this project I think it also built with MinGW

[jsulm]

@lucas_1603 I'm not a Windows expert, but I think you really need .lib file on Windows at build time, not .dll

[Lucas_1603]

@jsulm Yes, I'll try to find it out. Anw, thank you so much for your time, you helped me a lot

[SGaist]

Hi,

One other thing that you can try is to link directly to the static .a library. Use the full path to that file using $$PWD.

[raven-worx]

@lucas_1603
rename taglib.dll.a to taglib.a

Also read this

[Lucas_1603]

@sgaist I tried this:

LIBS += -L$$PWD/myTaglib -llibtag.dll.a

But the linker said "cannot find -llibtag.dll.a"

[SGaist]

As already suggested, try with LIBS += -l$$PWD/myTagLib/libtag.dll.a