CMAKE_PROJECT_VERSION

The version of the top level project.

This variable holds the version of the project as specified in the top level CMakeLists.txt file by a project() command. In the event that the top level CMakeLists.txt contains multiple project() calls, the most recently called one from that top level CMakeLists.txt will determine the value that CMAKE_PROJECT_VERSION contains. For example, consider the following top level CMakeLists.txt:

cmake_minimum_required(VERSION 3.0)
project(First VERSION 1.2.3)
project(Second VERSION 3.4.5)
add_subdirectory(sub)
project(Third VERSION 6.7.8)

And sub/CMakeLists.txt with the following contents:

project(SubProj VERSION 1)
message("CMAKE_PROJECT_VERSION = ${CMAKE_PROJECT_VERSION}")

The most recently seen project() command from the top level CMakeLists.txt would be project(Second ...), so this will print:

CMAKE_PROJECT_VERSION = 3.4.5

To obtain the version from the most recent call to project() in the current directory scope or above, see the PROJECT_VERSION variable.