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Diffstat (limited to 'Help/command/cmake_host_system_information.rst')
| -rw-r--r-- | Help/command/cmake_host_system_information.rst | 67 |
1 files changed, 67 insertions, 0 deletions
diff --git a/Help/command/cmake_host_system_information.rst b/Help/command/cmake_host_system_information.rst index ae24b03..66249ad 100644 --- a/Help/command/cmake_host_system_information.rst +++ b/Help/command/cmake_host_system_information.rst @@ -176,8 +176,75 @@ system identification as described in the `man 5 os-release`_. -- DISTRO_VERSION_CODENAME=`focal` -- DISTRO_VERSION_ID=`20.04` +If :file:`/etc/os-release` file is not found, the command tries to gather OS +identification via fallback scripts. The fallback script can use `various +distribution-specific files`_ to collect OS identification data and map it +into `man 5 os-release`_ variables. + +Fallback Interface Variables +^^^^^^^^^^^^^^^^^^^^^^^^^^^^ + +.. variable:: CMAKE_GET_OS_RELEASE_FALLBACK_SCRIPTS + + In addition to the scripts shipped with CMake, a user may append full + paths to his script(s) to the this list. The script filename has the + following format: ``NNN-<name>.cmake``, where ``NNN`` is three digits + used to apply collected scripts in a specific order. + +.. variable:: CMAKE_GET_OS_RELEASE_FALLBACK_RESULT_<varname> + + Variables collected by the user provided fallback script + ought to be assigned to CMake variables using this naming + convention. Example, the ``ID`` variable from the manual becomes + ``CMAKE_GET_OS_RELEASE_FALLBACK_RESULT_ID``. + +.. variable:: CMAKE_GET_OS_RELEASE_FALLBACK_RESULT + + The fallback script ought to store names of all assigned + ``CMAKE_GET_OS_RELEASE_FALLBACK_RESULT_<varname>`` variables in this list. + +Example: + +.. code-block:: cmake + + # Try to detect some old distribution + # See also + # - http://linuxmafia.com/faq/Admin/release-files.html + # + if(NOT EXISTS "${CMAKE_SYSROOT}/etc/foobar-release") + return() + endif() + # Get the first string only + file( + STRINGS "${CMAKE_SYSROOT}/etc/foobar-release" CMAKE_GET_OS_RELEASE_FALLBACK_CONTENT + LIMIT_COUNT 1 + ) + # + # Example: + # + # Foobar distribution release 1.2.3 (server) + # + if(CMAKE_GET_OS_RELEASE_FALLBACK_CONTENT MATCHES "Foobar distribution release ([0-9\.]+) .*") + set(CMAKE_GET_OS_RELEASE_FALLBACK_RESULT_NAME Foobar) + set(CMAKE_GET_OS_RELEASE_FALLBACK_RESULT_PRETTY_NAME "${CMAKE_GET_OS_RELEASE_FALLBACK_CONTENT}") + set(CMAKE_GET_OS_RELEASE_FALLBACK_RESULT_ID foobar) + set(CMAKE_GET_OS_RELEASE_FALLBACK_RESULT_VERSION ${CMAKE_MATCH_1}) + set(CMAKE_GET_OS_RELEASE_FALLBACK_RESULT_VERSION_ID ${CMAKE_MATCH_1}) + list( + APPEND CMAKE_GET_OS_RELEASE_FALLBACK_RESULT + CMAKE_GET_OS_RELEASE_FALLBACK_RESULT_NAME + CMAKE_GET_OS_RELEASE_FALLBACK_RESULT_PRETTY_NAME + CMAKE_GET_OS_RELEASE_FALLBACK_RESULT_ID + CMAKE_GET_OS_RELEASE_FALLBACK_RESULT_VERSION + CMAKE_GET_OS_RELEASE_FALLBACK_RESULT_VERSION_ID + ) + endif() + unset(CMAKE_GET_OS_RELEASE_FALLBACK_CONTENT) + + .. rubric:: Footnotes .. [#mebibytes] One MiB (mebibyte) is equal to 1024x1024 bytes. .. _man 5 os-release: https://www.freedesktop.org/software/systemd/man/os-release.html +.. _various distribution-specific files: http://linuxmafia.com/faq/Admin/release-files.html |