The project provides a set of macros to help bootstrap the creation of new projects.

A typical top level CMakeLists.txt file starts with these lines:

# 1
	cmake_minimum_required(VERSION 3.0.0)
	# 2
	project("ProjName" VERSION "0.0.1" LANGUAGES C CXX)
	# 3
	list (APPEND CMAKE_MODULE_PATH "$ENV{CMAKE_MODULE_PATH}")
	IF(WIN32)
		string(REPLACE "\\" "/" CMAKE_MODULE_PATH "${CMAKE_MODULE_PATH}")
	ENDIF()
	# 4
	include(pile_support)

It declares minimum CMake version (1) and provides a name for the project using standard project CMake command (2). This defines following variables with obvious content:

• PROJECT_SOURCE_DIR, <PROJECT-NAME>_SOURCE_DIR
• PROJECT_BINARY_DIR, <PROJECT-NAME>_BINARY_DIR
• PROJECT_VERSION, <PROJECT-NAME>_VERSION
• PROJECT_VERSION_MAJOR, <PROJECT-NAME>_VERSION_MAJOR
• PROJECT_VERSION_MINOR, <PROJECT-NAME>_VERSION_MINOR
• PROJECT_VERSION_PATCH, <PROJECT-NAME>_VERSION_PATCH
• PROJECT_VERSION_TWEAK, <PROJECT-NAME>_VERSION_TWEAK

By default Cmake does not inspect the content of CMAKE_MODULE_PATH environment variable, thus forcing the user to employ the -D... command line option. If such an environment variable was defined we can make use of it using script in 3; we take into account the fact that CMake expects it to have forward-slashes as path delimiters even in Windows environments.

Previous point is important because we need a way to find pile_support CMake script (4). It will make sure to include all other CMake helpers provided by the project.

The main part of the top-level CMake script has following format:

pileProject("1")

	pileProjectCommon()

	# add sub-directories here ...
	
	pileProjectEnd()

The pileProject macro adds a number of variables:

PROJECT_NAME:

the name of the project (CamelCased, with spaces)

PROJECT_NAME_UNIX:

the name of the project (low case, no spaces)

PROJECT_NAME_UPPER:

the name of the project (high case, no spaces)

<PROJECT-NAME>_MAJOR_VERSION:

major version

<PROJECT-NAME>_MINOR_VERSION:

minor version

<PROJECT-NAME>_PATCH_VERSION:

pathc/build number

<PROJECT-NAME>_SETTINGS_VERSION:

the version for settings

<PROJECT-NAME>_VERSION:

a string in the form "1.2.3"

TARGET_COMPILER_MSVC:

The compiler to be used is Microsoft compiler?

TARGET_SYSTEM_WIN32:

target system is Windows?

TARGET_SYSTEM_UNIX:

are we targeting unix?

<PROJECT-NAME>_DEBUG:

is this a debug build or a release build?

The pileProjectCommon invokes all common macros listed below. The user may choose to use only a subset of these macros.

• pileProjectCommonDebug
• pileProjectCommonModPaths
• pileProjectCommonOptions
• pileProjectCommonBuildDir
• pileProjectCommonIncludeDir
• pileProjectCommonBits
• pileProjectCommonQt
• pileProjectCommonPackage

The pileProjectEnd looks for a configuration file called config.h.in and, if it exists, uses the standard CMake configure_file command on it.
If a Doxyfile.in file exists and the user enabled appropriate option it is also run through same standard mechanism, Doxygeen is located and a target is created for building the documentation.
The macro also includes CPack, so all relevant variables should be assigned values before the invocation.