Help/manual/cmake-configure-log.7.rst - third_party/cmake - Git at Google

 .. cmake-manual-description: CMake Configure Log

 cmake-configure-log(7)
 **********************

 .. versionadded:: 3.26

 .. only:: html

    .. contents::

 Introduction
 ============

 CMake writes a running log, known as the *configure log*,
 of certain events that occur during the Configure step.
 The configure log does *not* contain a log of all output, errors,
 or messages printed while configuring a project.  It is a log of
 detailed information about specific events, such as toolchain inspection
 by :command:`try_compile`, meant for use in debugging the configuration
 of a build tree.

 For human use, this version of CMake writes the configure log to the file::

   ${CMAKE_BINARY_DIR}/CMakeFiles/CMakeConfigureLog.yaml

 However, the *location and name of the log file may change* in future
 versions of CMake.  Tools that read the configure log should get its
 location using a :ref:`configureLog <file-api configureLog>` query to
 the :manual:`cmake-file-api(7)`.
 See the `Log Versioning`_ section below for details.

 Log Structure
 =============

 The configure log is designed to be both machine- and human-readable.

 The log file is a YAML document stream containing zero or more YAML
 documents separated by document markers.  Each document begins
 with a ``---`` document marker line, contains a single YAML mapping
 that logs events from one CMake "configure" step, and, if the configure
 step finished normally, ends with a ``...`` document marker line:

 .. code-block:: yaml

   ---
   events:
     -
       kind: "try_compile-v1"
       # (other fields omitted)
     -
       kind: "try_compile-v1"
       # (other fields omitted)
   ...

 A new document is appended to the log every time CMake configures
 the build tree and logs new events.

 The keys of each document root mapping are:

 ``events``
   A YAML block sequence of nodes corresponding to events logged during
   one CMake "configure" step.  Each event is a YAML node containing one
   of the `Event Kinds`_ documented below.

 Log Versioning
 --------------

 Each of the `Event Kinds`_ is versioned independently.  The set of
 keys an event's log entry provides is specific to its major version.
 When an event is logged, the latest version of its event kind that is
 known to the running version of CMake is always written to the log.

 Tools reading the configure log must ignore event kinds and versions
 they do not understand:

 * A future version of CMake may introduce a new event kind or version.

 * If an existing build tree is re-configured with a different version of
   CMake, the log may contain different versions of the same event kind.

 * If :manual:`cmake-file-api(7)` queries request one or more
   :ref:`configureLog <file-api configureLog>` object versions,
   the log may contain multiple entries for the same event, each
   with a different version of its event kind.

 IDEs should write a :manual:`cmake-file-api(7)` query requesting a
 specific :ref:`configureLog <file-api configureLog>` object version,
 before running CMake, and then read the configure log only as described
 by the file-api reply.

 Text Block Encoding
 -------------------

 In order to make the log human-readable, text blocks are always
 represented using YAML literal block scalars (``|``).
 Since literal block scalars do not support escaping, backslashes
 and non-printable characters are encoded at the application layer:

 * ``\\`` encodes a backslash.
 * ``\xXX`` encodes a byte using two hexadecimal digits, ``XX``.

 .. _`configure-log event kinds`:

 Event Kinds
 ===========

 Every event kind is represented by a YAML mapping of the form:

 .. code-block:: yaml

   kind: "<kind>-v<major>"
   backtrace:
     - "<file>:<line> (<function>)"
   checks:
     - "Checking for something"
   #...event-specific keys...

 The keys common to all events are:

 ``kind``
   A string identifying the event kind and major version.

 ``backtrace``
   A YAML block sequence reporting the call stack of CMake source
   locations at which the event occurred, from most-recent to
   least-recent.  Each node is a string specifying one location
   formatted as ``<file>:<line> (<function>)``.

 ``checks``
   An optional key that is present when the event occurred with
   at least one pending :command:`message(CHECK_START)`.  Its value
   is a YAML block sequence reporting the stack of pending checks,
   from most-recent to least-recent.  Each node is a string containing
   a pending check message.

 Additional mapping keys are specific to each (versioned) event kind,
 described below.

 .. _`message configure-log event`:

 Event Kind ``message``
 ----------------------

 The :command:`message(CONFIGURE_LOG)` command logs ``message`` events.

 There is only one ``message`` event major version, version 1.

 .. _`message-v1 event`:

 ``message-v1`` Event
 ^^^^^^^^^^^^^^^^^^^^

 A ``message-v1`` event is a YAML mapping:

 .. code-block:: yaml

   kind: "message-v1"
   backtrace:
     - "CMakeLists.txt:123 (message)"
   checks:
     - "Checking for something"
   message: |
     # ...

 The keys specific to ``message-v1`` mappings are:

 ``message``
   A YAML literal block scalar containing the message text,
   represented using our `Text Block Encoding`_.

 .. _`try_compile configure-log event`:

 Event Kind ``try_compile``
 --------------------------

 The :command:`try_compile` command logs ``try_compile`` events.

 There is only one ``try_compile`` event major version, version 1.

 .. _`try_compile-v1 event`:

 ``try_compile-v1`` Event
 ^^^^^^^^^^^^^^^^^^^^^^^^

 A ``try_compile-v1`` event is a YAML mapping:

 .. code-block:: yaml

   kind: "try_compile-v1"
   backtrace:
     - "CMakeLists.txt:123 (try_compile)"
   checks:
     - "Checking for something"
   description: "Explicit LOG_DESCRIPTION"
   directories:
     source: "/path/to/.../TryCompile-01234"
     binary: "/path/to/.../TryCompile-01234"
   cmakeVariables:
     SOME_VARIABLE: "Some Value"
   buildResult:
     variable: "COMPILE_RESULT"
     cached: true
     stdout: |
       # ...
     exitCode: 0

 The keys specific to ``try_compile-v1`` mappings are:

 ``description``
   An optional key that is present when the ``LOG_DESCRIPTION <text>`` option
   was used.  Its value is a string containing the description ``<text>``.

 ``directories``
   A mapping describing the directories associated with the
   compilation attempt.  It has the following keys:

   ``source``
     String specifying the source directory of the
     :command:`try_compile` project.

   ``binary``
     String specifying the binary directory of the
     :command:`try_compile` project.
     For non-project invocations, this is often the same as
     the source directory.

 ``cmakeVariables``
   An optional key that is present when CMake propagates variables
   into the test project, either automatically or due to the
   :variable:`CMAKE_TRY_COMPILE_PLATFORM_VARIABLES` variable.
   Its value is a mapping from variable names to their values.

 ``buildResult``
   A mapping describing the result of compiling the test code.
   It has the following keys:

   ``variable``
     A string specifying the name of the CMake variable
     storing the result of trying to build the test project.

   ``cached``
     A boolean indicating whether the above result ``variable``
     is stored in the CMake cache.

   ``stdout``
     A YAML literal block scalar containing the output from building
     the test project, represented using our `Text Block Encoding`_.
     This contains build output from both stdout and stderr.

   ``exitCode``
     An integer specifying the build tool exit code from trying
     to build the test project.

 .. _`try_run configure-log event`:

 Event Kind ``try_run``
 ----------------------

 The :command:`try_run` command logs ``try_run`` events.

 There is only one ``try_run`` event major version, version 1.

 .. _`try_run-v1 event`:

 ``try_run-v1`` Event
 ^^^^^^^^^^^^^^^^^^^^

 A ``try_run-v1`` event is a YAML mapping:

 .. code-block:: yaml

   kind: "try_run-v1"
   backtrace:
     - "CMakeLists.txt:456 (try_run)"
   checks:
     - "Checking for something"
   description: "Explicit LOG_DESCRIPTION"
   directories:
     source: "/path/to/.../TryCompile-56789"
     binary: "/path/to/.../TryCompile-56789"
   buildResult:
     variable: "COMPILE_RESULT"
     cached: true
     stdout: |
       # ...
     exitCode: 0
   runResult:
     variable: "RUN_RESULT"
     cached: true
     stdout: |
       # ...
     stderr: |
       # ...
     exitCode: 0

 The keys specific to ``try_run-v1`` mappings include those
 documented by the `try_compile-v1 event`_, plus:

 ``runResult``
   A mapping describing the result of running the test code.
   It has the following keys:

   ``variable``
     A string specifying the name of the CMake variable
     storing the result of trying to run the test executable.

   ``cached``
     A boolean indicating whether the above result ``variable``
     is stored in the CMake cache.

   ``stdout``
     An optional key that is present when the test project built successfully.
     Its value is a YAML literal block scalar containing output from running
     the test executable, represented using our `Text Block Encoding`_.

     If ``RUN_OUTPUT_VARIABLE`` was used, stdout and stderr are captured
     together, so this will contain both.  Otherwise, this will contain
     only the stdout output.

   ``stderr``
     An optional key that is present when the test project built successfully
     and the ``RUN_OUTPUT_VARIABLE`` option was not used.
     Its value is a YAML literal block scalar containing output from running
     the test executable, represented using our `Text Block Encoding`_.

     If ``RUN_OUTPUT_VARIABLE`` was used, stdout and stderr are captured
     together in the ``stdout`` key, and this key will not be present.
     Otherwise, this will contain the stderr output.

   ``exitCode``
     An optional key that is present when the test project built successfully.
     Its value is an integer specifying the exit code, or a string containing
     an error message, from trying to run the test executable.
	.. cmake-manual-description: CMake Configure Log

	cmake-configure-log(7)
	**********************

	.. versionadded:: 3.26

	.. only:: html

	.. contents::

	Introduction
	============

	CMake writes a running log, known as the configure log,
	of certain events that occur during the Configure step.
	The configure log does not contain a log of all output, errors,
	or messages printed while configuring a project. It is a log of
	detailed information about specific events, such as toolchain inspection
	by :command:`try_compile`, meant for use in debugging the configuration
	of a build tree.

	For human use, this version of CMake writes the configure log to the file::

	${CMAKE_BINARY_DIR}/CMakeFiles/CMakeConfigureLog.yaml

	However, the location and name of the log file may change in future
	versions of CMake. Tools that read the configure log should get its
	location using a :ref:`configureLog <file-api configureLog>` query to
	the :manual:`cmake-file-api(7)`.
	See the `Log Versioning`_ section below for details.

	Log Structure
	=============

	The configure log is designed to be both machine- and human-readable.

	The log file is a YAML document stream containing zero or more YAML
	documents separated by document markers. Each document begins
	with a ``---`` document marker line, contains a single YAML mapping
	that logs events from one CMake "configure" step, and, if the configure
	step finished normally, ends with a ``...`` document marker line:

	.. code-block:: yaml

	---
	events:
	-
	kind: "try_compile-v1"
	# (other fields omitted)
	-
	kind: "try_compile-v1"
	# (other fields omitted)
	...

	A new document is appended to the log every time CMake configures
	the build tree and logs new events.

	The keys of each document root mapping are:

	``events``
	A YAML block sequence of nodes corresponding to events logged during
	one CMake "configure" step. Each event is a YAML node containing one
	of the `Event Kinds`_ documented below.

	Log Versioning
	--------------

	Each of the `Event Kinds`_ is versioned independently. The set of
	keys an event's log entry provides is specific to its major version.
	When an event is logged, the latest version of its event kind that is
	known to the running version of CMake is always written to the log.

	Tools reading the configure log must ignore event kinds and versions
	they do not understand:

	* A future version of CMake may introduce a new event kind or version.

	* If an existing build tree is re-configured with a different version of
	CMake, the log may contain different versions of the same event kind.

	* If :manual:`cmake-file-api(7)` queries request one or more
	:ref:`configureLog <file-api configureLog>` object versions,
	the log may contain multiple entries for the same event, each
	with a different version of its event kind.

	IDEs should write a :manual:`cmake-file-api(7)` query requesting a
	specific :ref:`configureLog <file-api configureLog>` object version,
	before running CMake, and then read the configure log only as described
	by the file-api reply.

	Text Block Encoding
	-------------------

	In order to make the log human-readable, text blocks are always
	represented using YAML literal block scalars (``\|``).
	Since literal block scalars do not support escaping, backslashes
	and non-printable characters are encoded at the application layer:

	* ``\\`` encodes a backslash.
	* ``\xXX`` encodes a byte using two hexadecimal digits, ``XX``.

	.. _`configure-log event kinds`:

	Event Kinds
	===========

	Every event kind is represented by a YAML mapping of the form:

	.. code-block:: yaml

	kind: "<kind>-v<major>"
	backtrace:
	- "<file>:<line> (<function>)"
	checks:
	- "Checking for something"
	#...event-specific keys...

	The keys common to all events are:

	``kind``
	A string identifying the event kind and major version.

	``backtrace``
	A YAML block sequence reporting the call stack of CMake source
	locations at which the event occurred, from most-recent to
	least-recent. Each node is a string specifying one location
	formatted as ``<file>:<line> (<function>)``.

	``checks``
	An optional key that is present when the event occurred with
	at least one pending :command:`message(CHECK_START)`. Its value
	is a YAML block sequence reporting the stack of pending checks,
	from most-recent to least-recent. Each node is a string containing
	a pending check message.

	Additional mapping keys are specific to each (versioned) event kind,
	described below.

	.. _`message configure-log event`:

	Event Kind ``message``
	----------------------

	The :command:`message(CONFIGURE_LOG)` command logs ``message`` events.

	There is only one ``message`` event major version, version 1.

	.. _`message-v1 event`:

	``message-v1`` Event
	^^^^^^^^^^^^^^^^^^^^

	A ``message-v1`` event is a YAML mapping:

	.. code-block:: yaml

	kind: "message-v1"
	backtrace:
	- "CMakeLists.txt:123 (message)"
	checks:
	- "Checking for something"
	message: \|
	# ...

	The keys specific to ``message-v1`` mappings are:

	``message``
	A YAML literal block scalar containing the message text,
	represented using our `Text Block Encoding`_.

	.. _`try_compile configure-log event`:

	Event Kind ``try_compile``
	--------------------------

	The :command:`try_compile` command logs ``try_compile`` events.

	There is only one ``try_compile`` event major version, version 1.

	.. _`try_compile-v1 event`:

	``try_compile-v1`` Event
	^^^^^^^^^^^^^^^^^^^^^^^^

	A ``try_compile-v1`` event is a YAML mapping:

	.. code-block:: yaml

	kind: "try_compile-v1"
	backtrace:
	- "CMakeLists.txt:123 (try_compile)"
	checks:
	- "Checking for something"
	description: "Explicit LOG_DESCRIPTION"
	directories:
	source: "/path/to/.../TryCompile-01234"
	binary: "/path/to/.../TryCompile-01234"
	cmakeVariables:
	SOME_VARIABLE: "Some Value"
	buildResult:
	variable: "COMPILE_RESULT"
	cached: true
	stdout: \|
	# ...
	exitCode: 0

	The keys specific to ``try_compile-v1`` mappings are:

	``description``
	An optional key that is present when the ``LOG_DESCRIPTION <text>`` option
	was used. Its value is a string containing the description ``<text>``.

	``directories``
	A mapping describing the directories associated with the
	compilation attempt. It has the following keys:

	``source``
	String specifying the source directory of the
	:command:`try_compile` project.

	``binary``
	String specifying the binary directory of the
	:command:`try_compile` project.
	For non-project invocations, this is often the same as
	the source directory.

	``cmakeVariables``
	An optional key that is present when CMake propagates variables
	into the test project, either automatically or due to the
	:variable:`CMAKE_TRY_COMPILE_PLATFORM_VARIABLES` variable.
	Its value is a mapping from variable names to their values.

	``buildResult``
	A mapping describing the result of compiling the test code.
	It has the following keys:

	``variable``
	A string specifying the name of the CMake variable
	storing the result of trying to build the test project.

	``cached``
	A boolean indicating whether the above result ``variable``
	is stored in the CMake cache.

	``stdout``
	A YAML literal block scalar containing the output from building
	the test project, represented using our `Text Block Encoding`_.
	This contains build output from both stdout and stderr.

	``exitCode``
	An integer specifying the build tool exit code from trying
	to build the test project.

	.. _`try_run configure-log event`:

	Event Kind ``try_run``
	----------------------

	The :command:`try_run` command logs ``try_run`` events.

	There is only one ``try_run`` event major version, version 1.

	.. _`try_run-v1 event`:

	``try_run-v1`` Event
	^^^^^^^^^^^^^^^^^^^^

	A ``try_run-v1`` event is a YAML mapping:

	.. code-block:: yaml

	kind: "try_run-v1"
	backtrace:
	- "CMakeLists.txt:456 (try_run)"
	checks:
	- "Checking for something"
	description: "Explicit LOG_DESCRIPTION"
	directories:
	source: "/path/to/.../TryCompile-56789"
	binary: "/path/to/.../TryCompile-56789"
	buildResult:
	variable: "COMPILE_RESULT"
	cached: true
	stdout: \|
	# ...
	exitCode: 0
	runResult:
	variable: "RUN_RESULT"
	cached: true
	stdout: \|
	# ...
	stderr: \|
	# ...
	exitCode: 0

	The keys specific to ``try_run-v1`` mappings include those
	documented by the `try_compile-v1 event`_, plus:

	``runResult``
	A mapping describing the result of running the test code.
	It has the following keys:

	``variable``
	A string specifying the name of the CMake variable
	storing the result of trying to run the test executable.

	``cached``
	A boolean indicating whether the above result ``variable``
	is stored in the CMake cache.

	``stdout``
	An optional key that is present when the test project built successfully.
	Its value is a YAML literal block scalar containing output from running
	the test executable, represented using our `Text Block Encoding`_.

	If ``RUN_OUTPUT_VARIABLE`` was used, stdout and stderr are captured
	together, so this will contain both. Otherwise, this will contain
	only the stdout output.

	``stderr``
	An optional key that is present when the test project built successfully
	and the ``RUN_OUTPUT_VARIABLE`` option was not used.
	Its value is a YAML literal block scalar containing output from running
	the test executable, represented using our `Text Block Encoding`_.

	If ``RUN_OUTPUT_VARIABLE`` was used, stdout and stderr are captured
	together in the ``stdout`` key, and this key will not be present.
	Otherwise, this will contain the stderr output.

	``exitCode``
	An optional key that is present when the test project built successfully.
	Its value is an integer specifying the exit code, or a string containing
	an error message, from trying to run the test executable.