本文例子是在《foundations of Qt Development》p462的 Building Complex Projects with QMake小节的基础上建立起来的，本次实验在Mac上进行的，前面的几张截图是在Win7上得来的，不必在意。
最终想要得到的目录结构：
step1 create root directory
step 2 create app directory
step3 create src directory
step 4 write content for src pro file
TARGET = base
VERSION = 0.1.0
CONFIG = static
DESTDIR = ../lib
INCLUDEPATH += ../include
DEPENDPATH += . ../include
SOURCES += base.cpp
HEADERS += base.h
The difference of DEPENDPATH and INCLUDEPATH: INCLUDEPATH is used to search header files, DEPENDPATH is important for recompile.
Relative discussion link: https://www.qtcentre.org/threads/17346-QMake-s-INCLUDEPATH-and-DEPENDPATH-problems
INCLUDEPATH is used during compilation to find included header files. DEPENDPATH is used to resolve dependencies between header and source files, eg. which source files need to be recompiled when certain header file changes. If you modify a header file in folder foo/ and foo/ is not listed in DEPENDPATH, nothing gets recompiled. If foo/ is listed in DEPENDPATH, source files depending on that header will get recompiled. Paths can be relative to the .pro file or absolute paths.
clang: error: invalid deployment target for -stdlib=libc++ (requires OS X 10.7 or later):
我们可以在pro file中人为设定deploy的version
QMAKE_MACOSX_DEPLOYMENT_TARGET = 10.13
message( "This is a message about deploy target: " )
message( $$QMAKE_MACOSX_DEPLOYMENT_TARGET )
在MacOS升级到10.14后，QT build工程的时候一直有10.14SDK没有被QT测试的警告信息：
我们可以加上：CONFIG += sdk_no_version_check 屏蔽这些烦人的警告。
查看build的东西：
运行程序：
工程上传于：https://github.com/theArcticOcean/qtLib/tree/master/complex
