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diff --git a/share/cmake-3.17/Help/command/target_precompile_headers.rst b/share/cmake-3.17/Help/command/target_precompile_headers.rst deleted file mode 100644 index 569c7eb..0000000 --- a/share/cmake-3.17/Help/command/target_precompile_headers.rst +++ /dev/null @@ -1,124 +0,0 @@ -target_precompile_headers -------------------------- - -Add a list of header files to precompile. - -Precompiling header files can speed up compilation by creating a partially -processed version of some header files, and then using that version during -compilations rather than repeatedly parsing the original headers. - -Main Form -^^^^^^^^^ - -.. code-block:: cmake - - target_precompile_headers(<target> - <INTERFACE|PUBLIC|PRIVATE> [header1...] - [<INTERFACE|PUBLIC|PRIVATE> [header2...] ...]) - -The command adds header files to the :prop_tgt:`PRECOMPILE_HEADERS` and/or -:prop_tgt:`INTERFACE_PRECOMPILE_HEADERS` target properties of ``<target>``. -The named ``<target>`` must have been created by a command such as -:command:`add_executable` or :command:`add_library` and must not be an -:ref:`ALIAS target <Alias Targets>`. - -The ``INTERFACE``, ``PUBLIC`` and ``PRIVATE`` keywords are required to -specify the scope of the following arguments. ``PRIVATE`` and ``PUBLIC`` -items will populate the :prop_tgt:`PRECOMPILE_HEADERS` property of -``<target>``. ``PUBLIC`` and ``INTERFACE`` items will populate the -:prop_tgt:`INTERFACE_PRECOMPILE_HEADERS` property of ``<target>`` -(:ref:`IMPORTED targets <Imported Targets>` only support ``INTERFACE`` items). -Repeated calls for the same ``<target>`` will append items in the order called. - -Projects should generally avoid using ``PUBLIC`` or ``INTERFACE`` for targets -that will be :ref:`exported <install(EXPORT)>`, or they should at least use -the ``$<BUILD_INTERFACE:...>`` generator expression to prevent precompile -headers from appearing in an installed exported target. Consumers of a target -should typically be in control of what precompile headers they use, not have -precompile headers forced on them by the targets being consumed (since -precompile headers are not typically usage requirements). A notable exception -to this is where an :ref:`interface library <Interface Libraries>` is created -to define a commonly used set of precompile headers in one place and then other -targets link to that interface library privately. In this case, the interface -library exists specifically to propagate the precompile headers to its -consumers and the consumer is effectively still in control, since it decides -whether to link to the interface library or not. - -The list of header files is used to generate a header file named -``cmake_pch.h|xx`` which is used to generate the precompiled header file -(``.pch``, ``.gch``, ``.pchi``) artifact. The ``cmake_pch.h|xx`` header -file will be force included (``-include`` for GCC, ``/FI`` for MSVC) to -all source files, so sources do not need to have ``#include "pch.h"``. - -Header file names specified with angle brackets (e.g. ``<unordered_map>``) or -explicit double quotes (escaped for the :manual:`cmake-language(7)`, -e.g. ``[["other_header.h"]]``) will be treated as is, and include directories -must be available for the compiler to find them. Other header file names -(e.g. ``project_header.h``) are interpreted as being relative to the current -source directory (e.g. :variable:`CMAKE_CURRENT_SOURCE_DIR`) and will be -included by absolute path. - -Arguments to ``target_precompile_headers()`` may use "generator expressions" -with the syntax ``$<...>``. -See the :manual:`cmake-generator-expressions(7)` manual for available -expressions. See the :manual:`cmake-compile-features(7)` manual for -information on compile features and a list of supported compilers. -The ``$<COMPILE_LANGUAGE:...>`` generator expression is particularly -useful for specifying a language-specific header to precompile for -only one language (e.g. ``CXX`` and not ``C``). For example: - -.. code-block:: cmake - - target_precompile_headers(myTarget - PUBLIC - project_header.h - "$<$<COMPILE_LANGUAGE:CXX>:cxx_only.h>" - PRIVATE - [["other_header.h"]] - <unordered_map> - ) - -When specifying angle brackets inside a :manual:`generator expression -<cmake-generator-expressions(7)>`, be sure to encode the closing ``>`` -as ``$<ANGLE-R>``. For example: - -.. code-block:: cmake - - target_precompile_headers(mylib PRIVATE - "$<$<COMPILE_LANGUAGE:C>:<stddef.h$<ANGLE-R>>" - "$<$<COMPILE_LANGUAGE:CXX>:<cstddef$<ANGLE-R>>" - ) - - -Reusing Precompile Headers -^^^^^^^^^^^^^^^^^^^^^^^^^^ - -The command also supports a second signature which can be used to specify that -one target re-uses a precompiled header file artefact from another target -instead of generating its own: - -.. code-block:: cmake - - target_precompile_headers(<target> REUSE_FROM <other_target>) - -This form sets the :prop_tgt:`PRECOMPILE_HEADERS_REUSE_FROM` property to -``<other_target>`` and adds a dependency such that ``<target>`` will depend -on ``<other_target>``. CMake will halt with an error if the -:prop_tgt:`PRECOMPILE_HEADERS` property of ``<target>`` is already set when -the ``REUSE_FROM`` form is used. - -.. note:: - - The ``REUSE_FROM`` form requires the same set of compiler options, - compiler flags and compiler definitions for both ``<target>`` and - ``<other_target>``. Some compilers (e.g. GCC) may issue a warning if the - precompiled header file cannot be used (``-Winvalid-pch``). - -See Also -^^^^^^^^ - -To disable precompile headers for specific targets, see the -:prop_tgt:`DISABLE_PRECOMPILE_HEADERS` target property. - -To prevent precompile headers from being used when compiling a specific -source file, see the :prop_sf:`SKIP_PRECOMPILE_HEADERS` source file property. |