@raven-worx said:

Once the compilation is finished it should at least have created a library linker file (.lib for MSVC) and a dll file (if you chose the "shared" option)

ok, after command mingw32-make install i get this structure of files:
C:\taglib\bin\ libtag.dll
C:\taglib\bin\libtag_c.dll
C:\taglib\bin\taglib-config.cmd
C:\taglib\include\ taglib\ .h files
C:\taglib\lib\pkgconfig\taglib.pc
C:\taglib\lib\pkgconfig\taglib_c.pc
C:\taglib\lib\ libtag.dll.a
C:\taglib\lib\libtag_c.dll.a

copy these files (maybe also the header files from the include folder) somewhere to your projects folder and add it to your project: QtCreator / manually

so i copied libtag.dll, libtag.dll.a and taglib folder to D:\qtproject\myprojectfolder
then added
win32: LIBS += -L$$PWD/ -llibtag
INCLUDEPATH += $$PWD/
DEPENDPATH += $$PWD/
to .pro file and
#include "taglib/fileref.h"
#include "taglib/taglib.h"
#include "taglib/tag.h"
to .cpp file

and it works!! great!! thanx =))

Since your on Linux, why not install the taglib devel package from your distribution ?

@Gagiopapinni
Okay, can you verify that this symbol is present in the static lib? (you could use "dependency walker" for that purpose)

Thanks. It worked

@shahriar25
Congrationations :)
Good work!

The solution from SGaist helped me out when I had the same error messages, many thanks!

@devbrs You certainly must check if taglib is null. And you must use toUTF8() instead of toAscii().

The last problem is that some of the string conversion functions in TagLib don't appear to work with the QString conversion functions.

Namely the functions that create c++ string and wstring objects:

QString::fromStdString(tag->title().to8Bit()); QString::fromStdWString(tag->title().toWString());

The functions that return c style string pointers do work:

QString::fromWCharArray(tag->title().toCWString()); QString(tag->title().toCString(true));

Now, why the string functions work on Linux and not on the Mac, I don't know. Perhaps you could delve into it.