[CMake] Automatically add a revision number to the CPack installer name

[Eric Noulard]

2012/3/8 Glenn Ramsey <gr at componic.co.nz>:
> Yes, you can use add_custom_command(...) to run a script to get the revision
> number, but I don't think you can use that to alter CPACK_PACKAGE_FILE_NAME,
> which has been set at cmake time.

This true but how wouldn't a revision update trigger a CMake re-run?

Whatever the reason if you want to change/alter/set a CPACK_xxx value
at CPack time ,
independently of CMakre re-run, you can use  a CPACK_PROJECT_CONFIG_FILE:

CPACK_PROJECT_CONFIG_FILE
       CPack-time project CPack configuration file.

       This file included at cpack time, once per generator after CPack has
       set CPACK_GENERATOR to the actual generator being used.  It allows
       per-generator setting of CPACK_* variables at cpack time.

In your CMakeLists.txt you have to:

set(CPACK_PROJECT_CONFIG_FILE ${CMAKE_CURRENT_SOURCE_DIR}/MyCPackConf.cmake)

then write the logic you want in MyCPackConf.cmake.

see:
http://www.cmake.org/Wiki/CMake:CPackPackageGenerators#Overall_usage_.28common_to_all_generators.29

This CPACK_PROJECT_CONFIG_FILE is a CMake script file loaded by CPack
(which includes
a CMake script interpreter) you cannot use non scriptable CMake command in there
(and no add_xxx to make it simple) but you can perfectly use
execute_process in order to run
some SCM commands.

You should be able to override CPACK_PACKAGE_FILE_NAME dynamically in there.
You have access to all CPACK_xxx variable value.

However, in this script file you do not have access to CMAKE_xxx
variables you can usually access in CMakeLists.txt
(no CMAKE_PROJECT_NAME, nor orther variables YOU defined in the CMakeLists.txt
 besides CPACK_xxx ones)
If you need some of these values you'll have to create a
MyCPackConf.cmake.in
which will be configured **at CMake-time**
into
MyCPackConf.cmake

CMake itself is using this with the "CMakeCPackOptions.cmake.in" file
at the root of CMake
sources.
-- 
Erk
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