mirror of
https://github.com/pybind/pybind11.git
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77710ff01c
Under MSVC we were ignoring PYBIND11_CPP_STANDARD and simply not passing any standard (which makes MSVC default to its C++14 mode). MSVC 2015u3 added the `/std:c++14` and `/std:c++latest` flags; the latter, under MSVC 2017, enables some C++17 features (such as `std::optional` and `std::variant`), so it is something we need to start supporting under MSVC. This makes the PYBIND11_CPP_STANDARD cmake variable work under MSVC, defaulting it to /std:c++14 (matching the default -std=c++14 for non-MSVC). It also adds a new appveyor test running under MSVC 2017 with /std:c++latest, which runs (and passes) the `std::optional`/`std::variant` tests. Also updated the documentation to clarify the c++ flags and add show MSVC flag examples.
200 lines
7.9 KiB
CMake
200 lines
7.9 KiB
CMake
# tools/pybind11Tools.cmake -- Build system for the pybind11 modules
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#
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# Copyright (c) 2015 Wenzel Jakob <wenzel@inf.ethz.ch>
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#
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# All rights reserved. Use of this source code is governed by a
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# BSD-style license that can be found in the LICENSE file.
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cmake_minimum_required(VERSION 2.8.12)
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# Add a CMake parameter for choosing a desired Python version
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if(NOT PYBIND11_PYTHON_VERSION)
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set(PYBIND11_PYTHON_VERSION "" CACHE STRING "Python version to use for compiling modules")
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endif()
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set(Python_ADDITIONAL_VERSIONS 3.7 3.6 3.5 3.4)
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find_package(PythonLibsNew ${PYBIND11_PYTHON_VERSION} REQUIRED)
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include(CheckCXXCompilerFlag)
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include(CMakeParseArguments)
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function(select_cxx_standard)
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if(NOT PYBIND11_CPP_STANDARD)
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if(NOT MSVC)
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check_cxx_compiler_flag("-std=c++14" HAS_CPP14_FLAG)
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check_cxx_compiler_flag("-std=c++11" HAS_CPP11_FLAG)
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if (HAS_CPP14_FLAG)
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set(PYBIND11_CPP_STANDARD -std=c++14)
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elseif (HAS_CPP11_FLAG)
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set(PYBIND11_CPP_STANDARD -std=c++11)
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else()
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message(FATAL_ERROR "Unsupported compiler -- pybind11 requires C++11 support!")
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endif()
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elseif(MSVC)
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set(PYBIND11_CPP_STANDARD /std:c++14)
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endif()
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set(PYBIND11_CPP_STANDARD ${PYBIND11_CPP_STANDARD} CACHE STRING
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"C++ standard flag, e.g. -std=c++11, -std=c++14, /std:c++14. Defaults to C++14 mode." FORCE)
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endif()
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endfunction()
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# Checks whether the given CXX/linker flags can compile and link a cxx file. cxxflags and
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# linkerflags are lists of flags to use. The result variable is a unique variable name for each set
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# of flags: the compilation result will be cached base on the result variable. If the flags work,
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# sets them in cxxflags_out/linkerflags_out internal cache variables (in addition to ${result}).
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function(_pybind11_return_if_cxx_and_linker_flags_work result cxxflags linkerflags cxxflags_out linkerflags_out)
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set(CMAKE_REQUIRED_LIBRARIES ${linkerflags})
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check_cxx_compiler_flag("${cxxflags}" ${result})
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if (${result})
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set(${cxxflags_out} "${cxxflags}" CACHE INTERNAL "" FORCE)
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set(${linkerflags_out} "${linkerflags}" CACHE INTERNAL "" FORCE)
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endif()
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endfunction()
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# Internal: find the appropriate link time optimization flags for this compiler
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function(_pybind11_add_lto_flags target_name prefer_thin_lto)
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if (NOT DEFINED PYBIND11_LTO_CXX_FLAGS)
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set(PYBIND11_LTO_CXX_FLAGS "" CACHE INTERNAL "")
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set(PYBIND11_LTO_LINKER_FLAGS "" CACHE INTERNAL "")
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if(CMAKE_CXX_COMPILER_ID MATCHES "GNU|Clang")
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set(cxx_append "")
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set(linker_append "")
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if (CMAKE_CXX_COMPILER_ID MATCHES "Clang" AND NOT APPLE)
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# Clang Gold plugin does not support -Os; append -O3 to MinSizeRel builds to override it
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set(linker_append ";$<$<CONFIG:MinSizeRel>:-O3>")
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elseif(CMAKE_CXX_COMPILER_ID MATCHES "GNU")
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set(cxx_append ";-fno-fat-lto-objects")
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endif()
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if (CMAKE_CXX_COMPILER_ID MATCHES "Clang" AND prefer_thin_lto)
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_pybind11_return_if_cxx_and_linker_flags_work(HAS_FLTO_THIN
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"-flto=thin${cxx_append}" "-flto=thin${linker_append}"
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PYBIND11_LTO_CXX_FLAGS PYBIND11_LTO_LINKER_FLAGS)
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endif()
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if (NOT HAS_FLTO_THIN)
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_pybind11_return_if_cxx_and_linker_flags_work(HAS_FLTO
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"-flto${cxx_append}" "-flto${linker_append}"
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PYBIND11_LTO_CXX_FLAGS PYBIND11_LTO_LINKER_FLAGS)
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endif()
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elseif (CMAKE_CXX_COMPILER_ID MATCHES "Intel")
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# Intel equivalent to LTO is called IPO
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_pybind11_return_if_cxx_and_linker_flags_work(HAS_INTEL_IPO
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"-ipo" "-ipo" PYBIND11_LTO_CXX_FLAGS PYBIND11_LTO_LINKER_FLAGS)
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elseif(MSVC)
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# cmake only interprets libraries as linker flags when they start with a - (otherwise it
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# converts /LTCG to \LTCG as if it was a Windows path). Luckily MSVC supports passing flags
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# with - instead of /, even if it is a bit non-standard:
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_pybind11_return_if_cxx_and_linker_flags_work(HAS_MSVC_GL_LTCG
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"/GL" "-LTCG" PYBIND11_LTO_CXX_FLAGS PYBIND11_LTO_LINKER_FLAGS)
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endif()
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if (PYBIND11_LTO_CXX_FLAGS)
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message(STATUS "LTO enabled")
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else()
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message(STATUS "LTO disabled (not supported by the compiler and/or linker)")
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endif()
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endif()
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# Enable LTO flags if found, except for Debug builds
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if (PYBIND11_LTO_CXX_FLAGS)
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target_compile_options(${target_name} PRIVATE "$<$<NOT:$<CONFIG:Debug>>:${PYBIND11_LTO_CXX_FLAGS}>")
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endif()
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if (PYBIND11_LTO_LINKER_FLAGS)
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target_link_libraries(${target_name} PRIVATE "$<$<NOT:$<CONFIG:Debug>>:${PYBIND11_LTO_LINKER_FLAGS}>")
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endif()
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endfunction()
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# Build a Python extension module:
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# pybind11_add_module(<name> [MODULE | SHARED] [EXCLUDE_FROM_ALL]
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# [NO_EXTRAS] [THIN_LTO] source1 [source2 ...])
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#
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function(pybind11_add_module target_name)
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set(options MODULE SHARED EXCLUDE_FROM_ALL NO_EXTRAS THIN_LTO)
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cmake_parse_arguments(ARG "${options}" "" "" ${ARGN})
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if(ARG_MODULE AND ARG_SHARED)
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message(FATAL_ERROR "Can't be both MODULE and SHARED")
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elseif(ARG_SHARED)
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set(lib_type SHARED)
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else()
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set(lib_type MODULE)
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endif()
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if(ARG_EXCLUDE_FROM_ALL)
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set(exclude_from_all EXCLUDE_FROM_ALL)
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endif()
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add_library(${target_name} ${lib_type} ${exclude_from_all} ${ARG_UNPARSED_ARGUMENTS})
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target_include_directories(${target_name}
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PRIVATE ${PYBIND11_INCLUDE_DIR} # from project CMakeLists.txt
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PRIVATE ${pybind11_INCLUDE_DIR} # from pybind11Config
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PRIVATE ${PYTHON_INCLUDE_DIRS})
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# The prefix and extension are provided by FindPythonLibsNew.cmake
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set_target_properties(${target_name} PROPERTIES PREFIX "${PYTHON_MODULE_PREFIX}")
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set_target_properties(${target_name} PROPERTIES SUFFIX "${PYTHON_MODULE_EXTENSION}")
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if(WIN32 OR CYGWIN)
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# Link against the Python shared library on Windows
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target_link_libraries(${target_name} PRIVATE ${PYTHON_LIBRARIES})
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elseif(APPLE)
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# It's quite common to have multiple copies of the same Python version
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# installed on one's system. E.g.: one copy from the OS and another copy
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# that's statically linked into an application like Blender or Maya.
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# If we link our plugin library against the OS Python here and import it
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# into Blender or Maya later on, this will cause segfaults when multiple
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# conflicting Python instances are active at the same time (even when they
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# are of the same version).
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# Windows is not affected by this issue since it handles DLL imports
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# differently. The solution for Linux and Mac OS is simple: we just don't
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# link against the Python library. The resulting shared library will have
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# missing symbols, but that's perfectly fine -- they will be resolved at
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# import time.
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target_link_libraries(${target_name} PRIVATE "-undefined dynamic_lookup")
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if(ARG_SHARED)
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# Suppress CMake >= 3.0 warning for shared libraries
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set_target_properties(${target_name} PROPERTIES MACOSX_RPATH ON)
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endif()
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endif()
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select_cxx_standard()
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# Make sure C++11/14 are enabled
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target_compile_options(${target_name} PUBLIC ${PYBIND11_CPP_STANDARD})
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if(ARG_NO_EXTRAS)
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return()
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endif()
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_pybind11_add_lto_flags(${target_name} ${ARG_THIN_LTO})
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if (NOT MSVC AND NOT ${CMAKE_BUILD_TYPE} MATCHES Debug)
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# Set the default symbol visibility to hidden (very important to obtain small binaries)
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target_compile_options(${target_name} PRIVATE "-fvisibility=hidden")
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# Strip unnecessary sections of the binary on Linux/Mac OS
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if(CMAKE_STRIP)
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if(APPLE)
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add_custom_command(TARGET ${target_name} POST_BUILD
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COMMAND ${CMAKE_STRIP} -x $<TARGET_FILE:${target_name}>)
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else()
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add_custom_command(TARGET ${target_name} POST_BUILD
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COMMAND ${CMAKE_STRIP} $<TARGET_FILE:${target_name}>)
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endif()
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endif()
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endif()
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if(MSVC)
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# /MP enables multithreaded builds (relevant when there are many files), /bigobj is
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# needed for bigger binding projects due to the limit to 64k addressable sections
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target_compile_options(${target_name} PRIVATE /MP /bigobj)
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endif()
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endfunction()
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