與一個大四的學生同做一個項目，源文件有幾十個，剛開始還在為寫makefile發愁，幸好找到了automake工具鏈，覺得真是省了不少事。
后來他跟我說他用的是qmake,比用automake更省了不少事。一比較，發現qmake確實是一個更好地選擇。
automake工具鏈比較復雜。一般要autoscan+修改configure.in+aclocal+寫Makefile.am+configure+make。很不容易上手，而且
容易出錯。automake提供了更為精細的控制，復雜但強大。但其實一般我們也用不了那么多的功能，而且中間生成的那些配置文件也不在
少數。這時候還要將源碼與makefile部分分離開來。一般的開源軟件就采用這種方法，文件層次清楚，易于管理。但是一般的很少的文件
的話，我覺得用qmake就足夠了，易于上手，也不易出錯。
qmake一般是qmake -project/qmake/make三步，中間需要適當地修改生成的*.pro文件，然后就差不多了。qmake -project主要就是用
來生成*.pro文件。主要做的就是讀入當前目錄的源文件。一些常用的配置變量如下：
| Variable | Contents |
|---|
| CONFIG | General project configuration options. |
| DESTDIR | The directory in which the executable or binary file will be placed. |
| FORMS | A list of UI files to be processed by uic. |
| HEADERS | A list of filenames of header (.h) files used when building the project. |
| QT | Qt-specific configuration options. |
| RESOURCES | A list of resource (.rc) files to be included in the final project. See the The Qt Resource System for more information about these files. |
| SOURCES | A list of source code files to be used when building the project. |
| TEMPLATE | The template to use for the project. This determines whether the output of the build process will be an application, a library, or a plugin. |
變量之間可以相互賦值比如。
TEMP_SOURCES = $$SOURCES
Template變量比較重要：用來決定所建工程的類型：
| Template | Description of qmake output |
|---|
| app (default) | Creates a Makefile to build an application. |
| lib | Creates a Makefile to build a library. |
| subdirs | Creates a Makefile containing rules for the subdirectories specified using the SUBDIRSvariable. Each subdirectory must contain its own project file. |
| vcapp | Creates a Visual Studio Project file to build an application. |
| vclib | Creates a Visual Studio Project file to build a library. |
| vcsubdirs | Creates a Visual Studio Solution file to build projects in sub-directories. |
再說上面的config變量，內置的有：
| Option | Description |
|---|
| release | The project is to be built in release mode. This is ignored if debug is also specified. |
| debug | The project is to be built in debug mode. |
| debug_and_release | The project is built in both debug and release modes. |
| debug_and_release_target | The project is built in both debug and release modes. TARGET is built intoboth the debug and release directories. |
| build_all | If debug_and_release is specified, the project is built in both debug and release modes by default. |
| autogen_precompile_source | Automatically generates a .cpp file that includes the precompiled header file specified in the .pro file. |
| ordered | When using the subdirs template, this option specifies that the directories listed should be processed in the order in which they are given. |
| warn_on | The compiler should output as many warnings as possible. This is ignored ifwarn_off is specified. |
| warn_off | The compiler should output as few warnings as possible. |
| copy_dir_files | Enables the install rule to also copy directories, not just files. |
debug_and_release建立兩個版本。config還可以加上qt,thread,X11等用來指定建立相應的工程類型。
如果是qt工程的話，QT變量就是一個需要關注的對象。當用到相應的庫時，就要加上相應的名字比如：
常用的就是core,gui.其他的用到時加上就行。
另外一個比較重要問題就是QT與其他庫的融合，LIBS和INCLUDEPATH可以做到這一點。看名字就知道其作用。
和Gcc命令行參數的用法類似。
qmake也有一些內置的函數用來提供更為強大的功能。常用到的有include,可以用來包含其他的工程文件，類似于C的頭文件。還有條件控制類的，如：
win32 { SOURCES += paintwidget_win.cpp }
EXTRAS = handlers tests docs for(dir, EXTRAS) { exists($$dir) { SUBDIRS += $$dir } }