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# Distributed under the OSI-approved BSD 3-Clause License. See accompanying
# file Copyright.txt or https://cmake.org/licensing for details.
#[=======================================================================[.rst:
GenerateExportHeader
--------------------
Function for generation of export macros for libraries
This module provides the function ``GENERATE_EXPORT_HEADER()``.
.. versionadded:: 3.12
Added support for C projects. Previous versions supported C++ project only.
The ``GENERATE_EXPORT_HEADER`` function can be used to generate a file
suitable for preprocessor inclusion which contains EXPORT macros to be
used in library classes::
GENERATE_EXPORT_HEADER( LIBRARY_TARGET
[BASE_NAME <base_name>]
[EXPORT_MACRO_NAME <export_macro_name>]
[EXPORT_FILE_NAME <export_file_name>]
[DEPRECATED_MACRO_NAME <deprecated_macro_name>]
[NO_EXPORT_MACRO_NAME <no_export_macro_name>]
[INCLUDE_GUARD_NAME <include_guard_name>]
[STATIC_DEFINE <static_define>]
[NO_DEPRECATED_MACRO_NAME <no_deprecated_macro_name>]
[DEFINE_NO_DEPRECATED]
[PREFIX_NAME <prefix_name>]
[CUSTOM_CONTENT_FROM_VARIABLE <variable>]
)
The target properties :prop_tgt:`CXX_VISIBILITY_PRESET <<LANG>_VISIBILITY_PRESET>`
and :prop_tgt:`VISIBILITY_INLINES_HIDDEN` can be used to add the appropriate
compile flags for targets. See the documentation of those target properties,
and the convenience variables
:variable:`CMAKE_CXX_VISIBILITY_PRESET <CMAKE_<LANG>_VISIBILITY_PRESET>` and
:variable:`CMAKE_VISIBILITY_INLINES_HIDDEN`.
By default ``GENERATE_EXPORT_HEADER()`` generates macro names in a file
name determined by the name of the library. This means that in the
simplest case, users of ``GenerateExportHeader`` will be equivalent to:
.. code-block:: cmake
set(CMAKE_CXX_VISIBILITY_PRESET hidden)
set(CMAKE_VISIBILITY_INLINES_HIDDEN 1)
add_library(somelib someclass.cpp)
generate_export_header(somelib)
install(TARGETS somelib DESTINATION ${LIBRARY_INSTALL_DIR})
install(FILES
someclass.h
${PROJECT_BINARY_DIR}/somelib_export.h DESTINATION ${INCLUDE_INSTALL_DIR}
)
And in the ABI header files:
.. code-block:: c++
#include "somelib_export.h"
class SOMELIB_EXPORT SomeClass {
...
};
The CMake fragment will generate a file in the
``${CMAKE_CURRENT_BINARY_DIR}`` called ``somelib_export.h`` containing the
macros ``SOMELIB_EXPORT``, ``SOMELIB_NO_EXPORT``, ``SOMELIB_DEPRECATED``,
``SOMELIB_DEPRECATED_EXPORT`` and ``SOMELIB_DEPRECATED_NO_EXPORT``.
They will be followed by content taken from the variable specified by
the ``CUSTOM_CONTENT_FROM_VARIABLE`` option, if any.
The resulting file should be installed with other headers in the library.
The ``BASE_NAME`` argument can be used to override the file name and the
names used for the macros:
.. code-block:: cmake
add_library(somelib someclass.cpp)
generate_export_header(somelib
BASE_NAME other_name
)
Generates a file called ``other_name_export.h`` containing the macros
``OTHER_NAME_EXPORT``, ``OTHER_NAME_NO_EXPORT`` and ``OTHER_NAME_DEPRECATED``
etc.
The ``BASE_NAME`` may be overridden by specifying other options in the
function. For example:
.. code-block:: cmake
add_library(somelib someclass.cpp)
generate_export_header(somelib
EXPORT_MACRO_NAME OTHER_NAME_EXPORT
)
creates the macro ``OTHER_NAME_EXPORT`` instead of ``SOMELIB_EXPORT``, but
other macros and the generated file name is as default:
.. code-block:: cmake
add_library(somelib someclass.cpp)
generate_export_header(somelib
DEPRECATED_MACRO_NAME KDE_DEPRECATED
)
creates the macro ``KDE_DEPRECATED`` instead of ``SOMELIB_DEPRECATED``.
If ``LIBRARY_TARGET`` is a static library, macros are defined without
values.
If the same sources are used to create both a shared and a static
library, the uppercased symbol ``${BASE_NAME}_STATIC_DEFINE`` should be
used when building the static library:
.. code-block:: cmake
add_library(shared_variant SHARED ${lib_SRCS})
add_library(static_variant ${lib_SRCS})
generate_export_header(shared_variant BASE_NAME libshared_and_static)
set_target_properties(static_variant PROPERTIES
COMPILE_FLAGS -DLIBSHARED_AND_STATIC_STATIC_DEFINE)
This will cause the export macros to expand to nothing when building
the static library.
If ``DEFINE_NO_DEPRECATED`` is specified, then a macro
``${BASE_NAME}_NO_DEPRECATED`` will be defined This macro can be used to
remove deprecated code from preprocessor output:
.. code-block:: cmake
option(EXCLUDE_DEPRECATED "Exclude deprecated parts of the library" FALSE)
if (EXCLUDE_DEPRECATED)
set(NO_BUILD_DEPRECATED DEFINE_NO_DEPRECATED)
endif()
generate_export_header(somelib ${NO_BUILD_DEPRECATED})
And then in somelib:
.. code-block:: c++
class SOMELIB_EXPORT SomeClass
{
public:
#ifndef SOMELIB_NO_DEPRECATED
SOMELIB_DEPRECATED void oldMethod();
#endif
};
.. code-block:: c++
#ifndef SOMELIB_NO_DEPRECATED
void SomeClass::oldMethod() { }
#endif
If ``PREFIX_NAME`` is specified, the argument will be used as a prefix to
all generated macros.
For example:
.. code-block:: cmake
generate_export_header(somelib PREFIX_NAME VTK_)
Generates the macros ``VTK_SOMELIB_EXPORT`` etc.
.. versionadded:: 3.1
Library target can be an ``OBJECT`` library.
.. versionadded:: 3.7
Added the ``CUSTOM_CONTENT_FROM_VARIABLE`` option.
.. versionadded:: 3.11
Added the ``INCLUDE_GUARD_NAME`` option.
::
ADD_COMPILER_EXPORT_FLAGS( [<output_variable>] )
.. deprecated:: 3.0
Set the target properties
:prop_tgt:`CXX_VISIBILITY_PRESET <<LANG>_VISIBILITY_PRESET>` and
:prop_tgt:`VISIBILITY_INLINES_HIDDEN` instead.
The ``ADD_COMPILER_EXPORT_FLAGS`` function adds ``-fvisibility=hidden`` to
:variable:`CMAKE_CXX_FLAGS <CMAKE_<LANG>_FLAGS>` if supported, and is a no-op
on Windows which does not need extra compiler flags for exporting support.
You may optionally pass a single argument to ``ADD_COMPILER_EXPORT_FLAGS``
that will be populated with the ``CXX_FLAGS`` required to enable visibility
support for the compiler/architecture in use.
#]=======================================================================]
include(CheckCompilerFlag)
include(CheckSourceCompiles)
# TODO: Install this macro separately?
macro(_check_cxx_compiler_attribute _ATTRIBUTE _RESULT)
check_source_compiles(CXX "${_ATTRIBUTE} int somefunc() { return 0; }
int main() { return somefunc();}" ${_RESULT}
)
endmacro()
# TODO: Install this macro separately?
macro(_check_c_compiler_attribute _ATTRIBUTE _RESULT)
check_source_compiles(C "${_ATTRIBUTE} int somefunc(void) { return 0; }
int main(void) { return somefunc();}" ${_RESULT}
)
endmacro()
macro(_test_compiler_hidden_visibility)
if(CMAKE_COMPILER_IS_GNUCXX AND CMAKE_CXX_COMPILER_VERSION VERSION_LESS "4.2")
set(GCC_TOO_OLD TRUE)
elseif(CMAKE_COMPILER_IS_GNUCC AND CMAKE_C_COMPILER_VERSION VERSION_LESS "4.2")
set(GCC_TOO_OLD TRUE)
elseif(CMAKE_CXX_COMPILER_ID STREQUAL "Intel" AND CMAKE_CXX_COMPILER_VERSION VERSION_LESS "12.0")
set(_INTEL_TOO_OLD TRUE)
endif()
# Exclude XL here because it misinterprets -fvisibility=hidden even though
# the check_compiler_flag passes
if(NOT GCC_TOO_OLD
AND NOT _INTEL_TOO_OLD
AND NOT WIN32
AND NOT CYGWIN
AND NOT CMAKE_CXX_COMPILER_ID MATCHES "^(IBMClang|XLClang|XL)$"
AND NOT CMAKE_CXX_COMPILER_ID MATCHES "^(PGI|NVHPC)$"
AND NOT CMAKE_CXX_COMPILER_ID MATCHES Watcom)
if (CMAKE_CXX_COMPILER_LOADED)
check_compiler_flag(CXX -fvisibility=hidden COMPILER_HAS_HIDDEN_VISIBILITY)
check_compiler_flag(CXX -fvisibility-inlines-hidden
COMPILER_HAS_HIDDEN_INLINE_VISIBILITY)
else()
check_compiler_flag(C -fvisibility=hidden COMPILER_HAS_HIDDEN_VISIBILITY)
check_compiler_flag(C -fvisibility-inlines-hidden
COMPILER_HAS_HIDDEN_INLINE_VISIBILITY)
endif()
endif()
endmacro()
macro(_test_compiler_has_deprecated)
# NOTE: Some Embarcadero compilers silently compile __declspec(deprecated)
# without error, but this is not a documented feature and the attribute does
# not actually generate any warnings.
if(CMAKE_CXX_COMPILER_ID MATCHES Borland
OR CMAKE_CXX_COMPILER_ID MATCHES Embarcadero
OR CMAKE_CXX_COMPILER_ID MATCHES HP
OR GCC_TOO_OLD
OR CMAKE_CXX_COMPILER_ID MATCHES "^(PGI|NVHPC)$"
OR CMAKE_CXX_COMPILER_ID MATCHES Watcom)
set(COMPILER_HAS_DEPRECATED "" CACHE INTERNAL
"Compiler support for a deprecated attribute")
else()
if (CMAKE_CXX_COMPILER_LOADED)
_check_cxx_compiler_attribute("__attribute__((__deprecated__))"
COMPILER_HAS_DEPRECATED_ATTR)
if(COMPILER_HAS_DEPRECATED_ATTR)
set(COMPILER_HAS_DEPRECATED "${COMPILER_HAS_DEPRECATED_ATTR}"
CACHE INTERNAL "Compiler support for a deprecated attribute")
else()
_check_cxx_compiler_attribute("__declspec(deprecated)"
COMPILER_HAS_DEPRECATED)
endif()
else()
_check_c_compiler_attribute("__attribute__((__deprecated__))"
COMPILER_HAS_DEPRECATED_ATTR)
if(COMPILER_HAS_DEPRECATED_ATTR)
set(COMPILER_HAS_DEPRECATED "${COMPILER_HAS_DEPRECATED_ATTR}"
CACHE INTERNAL "Compiler support for a deprecated attribute")
else()
_check_c_compiler_attribute("__declspec(deprecated)"
COMPILER_HAS_DEPRECATED)
endif()
endif()
endif()
endmacro()
get_filename_component(_GENERATE_EXPORT_HEADER_MODULE_DIR
"${CMAKE_CURRENT_LIST_FILE}" PATH)
macro(_DO_SET_MACRO_VALUES TARGET_LIBRARY)
set(DEFINE_DEPRECATED)
set(DEFINE_EXPORT)
set(DEFINE_IMPORT)
set(DEFINE_NO_EXPORT)
if (COMPILER_HAS_DEPRECATED_ATTR AND NOT WIN32)
set(DEFINE_DEPRECATED "__attribute__ ((__deprecated__))")
elseif(COMPILER_HAS_DEPRECATED)
set(DEFINE_DEPRECATED "__declspec(deprecated)")
endif()
get_property(type TARGET ${TARGET_LIBRARY} PROPERTY TYPE)
if(NOT ${type} STREQUAL "STATIC_LIBRARY")
if(WIN32 OR CYGWIN)
set(DEFINE_EXPORT "__declspec(dllexport)")
set(DEFINE_IMPORT "__declspec(dllimport)")
elseif(COMPILER_HAS_HIDDEN_VISIBILITY)
set(DEFINE_EXPORT "__attribute__((visibility(\"default\")))")
set(DEFINE_IMPORT "__attribute__((visibility(\"default\")))")
set(DEFINE_NO_EXPORT "__attribute__((visibility(\"hidden\")))")
endif()
endif()
endmacro()
macro(_DO_GENERATE_EXPORT_HEADER TARGET_LIBRARY)
# Option overrides
set(options DEFINE_NO_DEPRECATED)
set(oneValueArgs PREFIX_NAME BASE_NAME EXPORT_MACRO_NAME EXPORT_FILE_NAME
DEPRECATED_MACRO_NAME NO_EXPORT_MACRO_NAME STATIC_DEFINE
NO_DEPRECATED_MACRO_NAME CUSTOM_CONTENT_FROM_VARIABLE INCLUDE_GUARD_NAME)
set(multiValueArgs)
cmake_parse_arguments(_GEH "${options}" "${oneValueArgs}" "${multiValueArgs}"
${ARGN})
set(BASE_NAME "${TARGET_LIBRARY}")
if(_GEH_BASE_NAME)
set(BASE_NAME ${_GEH_BASE_NAME})
endif()
string(TOUPPER ${BASE_NAME} BASE_NAME_UPPER)
string(TOLOWER ${BASE_NAME} BASE_NAME_LOWER)
# Default options
set(EXPORT_MACRO_NAME "${_GEH_PREFIX_NAME}${BASE_NAME_UPPER}_EXPORT")
set(NO_EXPORT_MACRO_NAME "${_GEH_PREFIX_NAME}${BASE_NAME_UPPER}_NO_EXPORT")
set(EXPORT_FILE_NAME "${CMAKE_CURRENT_BINARY_DIR}/${BASE_NAME_LOWER}_export.h")
set(DEPRECATED_MACRO_NAME "${_GEH_PREFIX_NAME}${BASE_NAME_UPPER}_DEPRECATED")
set(STATIC_DEFINE "${_GEH_PREFIX_NAME}${BASE_NAME_UPPER}_STATIC_DEFINE")
set(NO_DEPRECATED_MACRO_NAME
"${_GEH_PREFIX_NAME}${BASE_NAME_UPPER}_NO_DEPRECATED")
if(_GEH_UNPARSED_ARGUMENTS)
message(FATAL_ERROR "Unknown keywords given to GENERATE_EXPORT_HEADER(): \"${_GEH_UNPARSED_ARGUMENTS}\"")
endif()
if(_GEH_EXPORT_MACRO_NAME)
set(EXPORT_MACRO_NAME ${_GEH_PREFIX_NAME}${_GEH_EXPORT_MACRO_NAME})
endif()
string(MAKE_C_IDENTIFIER ${EXPORT_MACRO_NAME} EXPORT_MACRO_NAME)
if(_GEH_EXPORT_FILE_NAME)
if(IS_ABSOLUTE ${_GEH_EXPORT_FILE_NAME})
set(EXPORT_FILE_NAME ${_GEH_EXPORT_FILE_NAME})
else()
set(EXPORT_FILE_NAME "${CMAKE_CURRENT_BINARY_DIR}/${_GEH_EXPORT_FILE_NAME}")
endif()
endif()
if(_GEH_DEPRECATED_MACRO_NAME)
set(DEPRECATED_MACRO_NAME ${_GEH_PREFIX_NAME}${_GEH_DEPRECATED_MACRO_NAME})
endif()
string(MAKE_C_IDENTIFIER ${DEPRECATED_MACRO_NAME} DEPRECATED_MACRO_NAME)
if(_GEH_NO_EXPORT_MACRO_NAME)
set(NO_EXPORT_MACRO_NAME ${_GEH_PREFIX_NAME}${_GEH_NO_EXPORT_MACRO_NAME})
endif()
string(MAKE_C_IDENTIFIER ${NO_EXPORT_MACRO_NAME} NO_EXPORT_MACRO_NAME)
if(_GEH_STATIC_DEFINE)
set(STATIC_DEFINE ${_GEH_PREFIX_NAME}${_GEH_STATIC_DEFINE})
endif()
string(MAKE_C_IDENTIFIER ${STATIC_DEFINE} STATIC_DEFINE)
if(_GEH_DEFINE_NO_DEPRECATED)
set(DEFINE_NO_DEPRECATED 1)
else()
set(DEFINE_NO_DEPRECATED 0)
endif()
if(_GEH_NO_DEPRECATED_MACRO_NAME)
set(NO_DEPRECATED_MACRO_NAME
${_GEH_PREFIX_NAME}${_GEH_NO_DEPRECATED_MACRO_NAME})
endif()
string(MAKE_C_IDENTIFIER ${NO_DEPRECATED_MACRO_NAME} NO_DEPRECATED_MACRO_NAME)
if(_GEH_INCLUDE_GUARD_NAME)
set(INCLUDE_GUARD_NAME ${_GEH_INCLUDE_GUARD_NAME})
else()
set(INCLUDE_GUARD_NAME "${EXPORT_MACRO_NAME}_H")
endif()
get_target_property(EXPORT_IMPORT_CONDITION ${TARGET_LIBRARY} DEFINE_SYMBOL)
if(NOT EXPORT_IMPORT_CONDITION)
set(EXPORT_IMPORT_CONDITION ${TARGET_LIBRARY}_EXPORTS)
endif()
string(MAKE_C_IDENTIFIER ${EXPORT_IMPORT_CONDITION} EXPORT_IMPORT_CONDITION)
if(_GEH_CUSTOM_CONTENT_FROM_VARIABLE)
if(DEFINED "${_GEH_CUSTOM_CONTENT_FROM_VARIABLE}")
set(CUSTOM_CONTENT "${${_GEH_CUSTOM_CONTENT_FROM_VARIABLE}}")
else()
set(CUSTOM_CONTENT "")
endif()
endif()
configure_file("${_GENERATE_EXPORT_HEADER_MODULE_DIR}/exportheader.cmake.in"
"${EXPORT_FILE_NAME}" @ONLY)
endmacro()
function(GENERATE_EXPORT_HEADER TARGET_LIBRARY)
get_property(type TARGET ${TARGET_LIBRARY} PROPERTY TYPE)
if(NOT ${type} STREQUAL "STATIC_LIBRARY"
AND NOT ${type} STREQUAL "SHARED_LIBRARY"
AND NOT ${type} STREQUAL "OBJECT_LIBRARY"
AND NOT ${type} STREQUAL "MODULE_LIBRARY")
message(WARNING "This macro can only be used with libraries")
return()
endif()
_test_compiler_hidden_visibility()
_test_compiler_has_deprecated()
_do_set_macro_values(${TARGET_LIBRARY})
_do_generate_export_header(${TARGET_LIBRARY} ${ARGN})
endfunction()
function(add_compiler_export_flags)
if(NOT CMAKE_MINIMUM_REQUIRED_VERSION VERSION_LESS 2.8.12)
message(DEPRECATION "The add_compiler_export_flags function is obsolete. Use the CXX_VISIBILITY_PRESET and VISIBILITY_INLINES_HIDDEN target properties instead.")
endif()
_test_compiler_hidden_visibility()
_test_compiler_has_deprecated()
option(USE_COMPILER_HIDDEN_VISIBILITY
"Use HIDDEN visibility support if available." ON)
mark_as_advanced(USE_COMPILER_HIDDEN_VISIBILITY)
if(NOT (USE_COMPILER_HIDDEN_VISIBILITY AND COMPILER_HAS_HIDDEN_VISIBILITY))
# Just return if there are no flags to add.
return()
endif()
set (EXTRA_FLAGS "-fvisibility=hidden")
if(COMPILER_HAS_HIDDEN_INLINE_VISIBILITY)
set (EXTRA_FLAGS "${EXTRA_FLAGS} -fvisibility-inlines-hidden")
endif()
# Either return the extra flags needed in the supplied argument, or to the
# CMAKE_CXX_FLAGS if no argument is supplied.
if(ARGC GREATER 0)
set(${ARGV0} "${EXTRA_FLAGS}" PARENT_SCOPE)
else()
string(APPEND CMAKE_CXX_FLAGS " ${EXTRA_FLAGS}")
set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS}" PARENT_SCOPE)
endif()
endfunction()
# FIXME(#24994): The following module(s) are included only for compatibility
# with projects that accidentally relied on them with CMake 3.26 and below.
include(CheckCCompilerFlag)
include(CheckCXXCompilerFlag)