(C++) cannot find -lQtCore, and I want it

link error: cannot find -lQtCore and I want it.

History

Caused while trying to solve the Qt FAQ How to cross-compile a Qt Creator project from Ubuntu to a windows executable?.

Cause

Operating system: Ubuntu 10.04 LTS Lucid Lynx

IDE: Qt Creator 2.0.0

Project type: GUI application

Compiler: G++ 4.4.1

Libraries used:

Qt: version 4.7.0 (32 bit)
STL: from GCC, shipped with Qt Creator 2.0.0

Qt project file


#-------------------------------------------------

#

# Project created by QtCreator 2010-09-23T19:13:58

#

#-------------------------------------------------

QT       += core

QT       -= gui

#LIBS += -L/usr/lib -lQtCore

#LIBS += -L/usr/local/lib -lQtCore

#LIBS += -L/usr/local/lib -lQtGui

TARGET = CppQtCrosscompileToWindowsExample1

CONFIG   += console

CONFIG   -= app_bundle

TEMPLATE = app

SOURCES += main.cpp

#Set the C compiler to the mingw32 C compiler

QMAKE_CC  = i586-mingw32msvc-gcc

#Set the C++ compiler to the mingw32 C++ compiler

QMAKE_CXX = i586-mingw32msvc-g++

#Set the linker to the mingw32 C++ compiler

QMAKE_LINK = i586-mingw32msvc-g++

main.cpp


#include <iostream>



int main()

{

  std::cout <<

    "I am developed under Unbuntu, "

    "and I will run under Windows\n";

}

Observations

A makefile is successfully produced. When calling make in the makefile's folder, the following command was shown to give the error:


make

i586-mingw32msvc-g++  -o CppQtCrosscompileToWindowsExample1 main.o -L/usr/lib -lQtCore -lpthread

Adding one,two or all of these lines below did not solve the problem:


LIBS += -L/usr/lib -lQtCore

LIBS += -L/usr/local/lib -lQtCore

LIBS += -L/usr/local/lib -lQtGui

If, in the makefile I change the following line:


LIBS          = $(SUBLIBS)  -L/usr/lib -L/usr/lib -L/usr/local/lib -lQtCore -lpthread

To this line:


LIBS          = $(SUBLIBS)

An then call make:


make

A Windows executable is produced.

Solution

Unknown.

My hypothesis: when cross-compiling, one needs to cros-compile the libraries first! In this case, QtCore!

Go back to Richel Bilderbeek's C++ page.

Go back to Richel Bilderbeek's homepage.