Hello,

I am very new to QT and having trouble with a particular issue understanding how importing libs works in Qt. I have a very simple default Qt project for the MinGW compiler and I need to use a custom string class compiled in Visual Studio 2008. (I don't have access to the source, and there are other libs I need to work besides this one as well).

#-------------------------------------------------
#
# Project created by QtCreator 2014-09-12T09:46:39
#
#-------------------------------------------------

QT += core gui

greaterThan(QT_MAJOR_VERSION, 4): QT += widgets

TARGET = QtNVCDemo
TEMPLATE = app


SOURCES += main.cpp\
mainwindow.cpp

HEADERS += mainwindow.h

FORMS += mainwindow.ui

win32: LIBS += -L$$PWD/../build-QtDemo-Desktop_Qt_5_3_MinGW_32bit-Debug/debug/ -lSString-4

INCLUDEPATH += $$PWD/../build-QtDemo-Desktop_Qt_5_3_MinGW_32bit-Debug/debug
DEPENDPATH += $$PWD/../build-QtDemo-Desktop_Qt_5_3_MinGW_32bit-Debug/debug

win32:!win32-g++: PRE_TARGETDEPS += $$PWD/../build-QtDemo-Desktop_Qt_5_3_MinGW_32bit-Debug/debug/SString-4.lib
else:win32-g++: PRE_TARGETDEPS += $$PWD/../build-QtDemo-Desktop_Qt_5_3_MinGW_32bit-Debug/debug/libSString-4.a
I get this error
:-1: error: No rule to make target 'C:/Users/bereall/QtDemo/../build-QtDemo-Desktop_Qt_5_3_MinGW_32bit-Debug/debug/libSString-4.a', needed by 'debug\QtDemo.exe'. Stop.
The import lines were done trying to link a static lib using the wizard. What are .a libs and how do you create them? If I try changing the Sstring-4.a to the lib which I have it just says the same error? Trying to compile without the target dependencies lines works but then when I try to create a SString class or add the header to my project it doesn't recognize SString. Do I have to use libs created with the same compiler or can I import other libs?

I just want to be able to import an external lib and be able to use its classes in my code. Haven't had any luck with reading old forum posts on this particular issue.

Also if you're just trying to develop for Windows Desktop is MinGW the right compiler or should I be using msvc2010 opengl?