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Merge pull request #276 from rpavlik/debug-cmake-gcc11
Cmake GCC11 fixes
2 parents e385e69 + 6b8f48b commit cd49672

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‎changes/sdk/pr.276.gh.OpenXR-SDK-Source.md‎

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---
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- issue.260.gh.OpenXR-SDK-Source
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- issue.1571.gl
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---
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- Fix detection of std::filesystem options on GCC 11 and newer.

‎src/cmake/StdFilesystemFlags.cmake‎

Lines changed: 82 additions & 44 deletions
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@@ -2,6 +2,8 @@
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#
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# SPDX-License-Identifier: BSL-1.0
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set(_FILESYSTEM_UTILS_DIR "${PROJECT_SOURCE_DIR}/src/common")
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if(MSVC AND MSVC_VERSION GREATER 1890)
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set(HAVE_FILESYSTEM_WITHOUT_LIB
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ON
@@ -18,87 +20,107 @@ if(MSVC AND MSVC_VERSION GREATER 1890)
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else()
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include(CheckCXXSourceCompiles)
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# This is just example code that is known to not compile if std::filesystem isn't working right
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###
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# Test Sources
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###
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# This is just example code that is known to not compile if std::filesystem isn't working right.
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# It depends on having the proper includes and `using namespace` so it can use the `is_regular_file`
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# function unqualified.
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# It is at the end of every test file below.
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set(_stdfs_test_source
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"int main() {
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(void)is_regular_file(\"/\");
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return 0;
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}
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"
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)
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set(_stdfs_conditions
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"// If the C++ macro is set to the version containing C++17, it must support
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// the final C++17 package
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#if __cplusplus >= 201703L
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#define USE_FINAL_FS 1
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#elif defined(_MSC_VER) && _MSC_VER >= 1900
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#if defined(_HAS_CXX17) && _HAS_CXX17
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// When MSC supports c++17 use <filesystem> package.
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#define USE_FINAL_FS 1
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#endif // !_HAS_CXX17
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// Right now, GCC still only supports the experimental filesystem items starting in GCC 6
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#elif (__GNUC__ >= 6)
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#define USE_EXPERIMENTAL_FS 1
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// If Clang, check for feature support
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#elif defined(__clang__) && (__cpp_lib_filesystem || __cpp_lib_experimental_filesystem)
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#if __cpp_lib_filesystem
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#define USE_FINAL_FS 1
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#else
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#define USE_EXPERIMENTAL_FS 1
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#endif
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#endif
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"
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)
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# This is preprocessor code included in all test compiles, which pulls in the conditions
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# originally found in filesystem_utils.cpp.
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#
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# It defines:
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# USE_FINAL_FS = 1 if it thinks we have the full std::filesystem in <filesystem> as in C++17
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# USE_EXPERIMENTAL_FS = 1 if it thinks we don't have the full c++17 filesystem, but should have
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# std::experimental::filesystem and <experimental/filesystem>
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#
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# Ideally the first condition (__cplusplus >= 201703L) would handle most cases,
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# however you're not supposed to report that unless you're fully conformant with all
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# of c++17, so you might have a c++17 build flag and the final filesystem library but
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# a lower __cplusplus value if some other part of the standard is missing.
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set(_stdfs_conditions "#include <stdfs_conditions.h>
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")
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# This should only compile if our common detection code decides on the
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# **final** (non-experimental) filesystem library.
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set(_stdfs_source
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"${_stdfs_conditions}
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#ifdef USE_FINAL_FS
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#if defined(USE_FINAL_FS) && USE_FINAL_FS
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#include <filesystem>
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using namespace std::filesystem;
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#endif
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${_stdfs_test_source}
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"
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)
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# This should only compile if our common detection code decides on the
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# **experimental** filesystem library.
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set(_stdfs_experimental_source
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"${_stdfs_conditions}
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#ifdef USE_EXPERIMENTAL_FS
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#if defined(USE_EXPERIMENTAL_FS) && USE_EXPERIMENTAL_FS
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#include <experimental/filesystem>
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using namespace std::experimental::filesystem;
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#endif
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${_stdfs_test_source}
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"
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)
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# This should compile if the common detection code decided that either
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# the experimental or final filesystem library is available.
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# We use this when trying to detect what library to link, if any:
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# earlier checks are the ones that care about how we include the headers.
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set(_stdfs_needlib_source
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"${_stdfs_conditions}
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#ifdef USE_FINAL_FS
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#if defined(USE_FINAL_FS) && USE_FINAL_FS
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#include <filesystem>
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using namespace std::filesystem;
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#endif
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#ifdef USE_EXPERIMENTAL_FS
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#if defined(USE_EXPERIMENTAL_FS) && USE_EXPERIMENTAL_FS
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#include <experimental/filesystem>
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using namespace std::experimental::filesystem;
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#endif
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${_stdfs_test_source}
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"
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)
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###
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# Identifying header/namespace and standards flags
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###
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# First, just look for the include.
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# We're checking if it compiles, not if the include exists,
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# because the source code uses similar conditionals to decide.
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# because the source code uses the same conditionals to decide.
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# (Static libraries are just object files, they don't get linked)
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set(CMAKE_TRY_COMPILE_TARGET_TYPE STATIC_LIBRARY)
105+
set(CMAKE_REQUIRED_INCLUDES "${_FILESYSTEM_UTILS_DIR}")
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unset(CMAKE_REQUIRED_LIBRARIES)
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unset(CMAKE_REQUIRED_FLAGS)
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check_cxx_source_compiles("${_stdfs_source}" HAVE_FILESYSTEM_IN_STD)
96-
check_cxx_source_compiles("${_stdfs_experimental_source}" HAVE_FILESYSTEM_IN_STDEXPERIMENTAL)
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if(CMAKE_CXX_COMPILER_ID STREQUAL "GNU" AND NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 11.0)
108+
# GCC 11+ defaults to C++17 mode and acts badly in these tests if we tell it to use a different version.
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set(HAVE_FILESYSTEM_IN_STD_17 ON)
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set(HAVE_FILESYSTEM_IN_STD OFF)
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else()
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set(CMAKE_REQUIRED_FLAGS "-DCMAKE_CXX_STANDARD=14 -DCMAKE_CXX_STANDARD_REQUIRED=TRUE")
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check_cxx_source_compiles("${_stdfs_source}" HAVE_FILESYSTEM_IN_STD)
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check_cxx_source_compiles("${_stdfs_experimental_source}" HAVE_FILESYSTEM_IN_STDEXPERIMENTAL)
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set(CMAKE_REQUIRED_FLAGS "-DCMAKE_CXX_STANDARD=17 -DCMAKE_CXX_STANDARD_REQUIRED=TRUE")
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check_cxx_source_compiles("${_stdfs_source}" HAVE_FILESYSTEM_IN_STD_17)
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unset(CMAKE_REQUIRED_FLAGS)
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# See if the "final" version builds if we try to specify C++17 explicitly
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set(CMAKE_REQUIRED_FLAGS "-DCMAKE_CXX_STANDARD=17 -DCMAKE_CXX_STANDARD_REQUIRED=TRUE")
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check_cxx_source_compiles("${_stdfs_source}" HAVE_FILESYSTEM_IN_STD_17)
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unset(CMAKE_REQUIRED_FLAGS)
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endif()
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122+
# If we found the final version of filesystem when specifying C++17 explicitly,
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# but found it no other way, then we record that we must use C++17 flags.
102124
if(HAVE_FILESYSTEM_IN_STD_17 AND NOT HAVE_FILESYSTEM_IN_STD)
103125
set(HAVE_FILESYSTEM_NEEDS_17
104126
ON
@@ -112,21 +134,37 @@ else()
112134
)
113135
endif()
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115-
# Now, see if we need libstdc++fs
137+
###
138+
# Identifying library to link
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###
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141+
# Now, see if we need to link against libstdc++fs, and what it's called
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# If we needed C++17 standard flags to find it, they've already been set above.
116143
set(CMAKE_TRY_COMPILE_TARGET_TYPE EXECUTABLE)
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145+
# Try with no lib specified
117146
check_cxx_source_compiles("${_stdfs_needlib_source}" HAVE_FILESYSTEM_WITHOUT_LIB)
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148+
# Try with stdc++fs
118149
set(CMAKE_REQUIRED_LIBRARIES stdc++fs)
119150
check_cxx_source_compiles("${_stdfs_needlib_source}" HAVE_FILESYSTEM_NEEDING_LIBSTDCXXFS)
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# Try with c++fs (from clang's libc++)
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set(CMAKE_REQUIRED_LIBRARIES c++fs)
121154
check_cxx_source_compiles("${_stdfs_needlib_source}" HAVE_FILESYSTEM_NEEDING_LIBCXXFS)
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# Clean up these variables before the next user.
122157
unset(CMAKE_REQUIRED_LIBRARIES)
123158
unset(CMAKE_TRY_COMPILE_TARGET_TYPE)
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unset(CMAKE_REQUIRED_INCLUDES)
125160
endif()
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# Use the observations of the code above to add the filesystem_utils.cpp
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# file to a target, along with any required compiler settings and libraries.
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# Also handles our BUILD_WITH_STD_FILESYSTEM option.
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function(openxr_add_filesystem_utils TARGET_NAME)
128-
target_sources(${TARGET_NAME} PRIVATE ${PROJECT_SOURCE_DIR}/src/common/filesystem_utils.cpp)
129-
target_include_directories(${TARGET_NAME} PRIVATE ${PROJECT_SOURCE_DIR}/src/common)
166+
target_sources(${TARGET_NAME} PRIVATE ${_FILESYSTEM_UTILS_DIR}/filesystem_utils.cpp)
167+
target_include_directories(${TARGET_NAME} PRIVATE ${_FILESYSTEM_UTILS_DIR})
130168
if(NOT BUILD_WITH_STD_FILESYSTEM)
131169
target_compile_definitions(${TARGET_NAME} PRIVATE DISABLE_STD_FILESYSTEM)
132170
else()

‎src/common/filesystem_utils.cpp‎

Lines changed: 1 addition & 34 deletions
Original file line numberDiff line numberDiff line change
@@ -20,40 +20,7 @@
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#define USE_FINAL_FS 0
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#else
23-
// If the C++ macro is set to the version containing C++17, it must support
24-
// the final C++17 package
25-
#if __cplusplus >= 201703L
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#define USE_EXPERIMENTAL_FS 0
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#define USE_FINAL_FS 1
28-
29-
#elif defined(_MSC_VER) && _MSC_VER >= 1900
30-
31-
#if defined(_HAS_CXX17) && _HAS_CXX17
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// When MSC supports c++17 use <filesystem> package.
33-
#define USE_EXPERIMENTAL_FS 0
34-
#define USE_FINAL_FS 1
35-
#endif // !_HAS_CXX17
36-
37-
// Right now, GCC still only supports the experimental filesystem items starting in GCC 6
38-
#elif (__GNUC__ >= 6)
39-
#define USE_EXPERIMENTAL_FS 1
40-
#define USE_FINAL_FS 0
41-
42-
// If Clang, check for feature support
43-
#elif defined(__clang__) && (__cpp_lib_filesystem || __cpp_lib_experimental_filesystem)
44-
#if __cpp_lib_filesystem
45-
#define USE_EXPERIMENTAL_FS 0
46-
#define USE_FINAL_FS 1
47-
#else
48-
#define USE_EXPERIMENTAL_FS 1
49-
#define USE_FINAL_FS 0
50-
#endif
51-
52-
// If all above fails, fall back to standard C++ and OS-specific items
53-
#else
54-
#define USE_EXPERIMENTAL_FS 0
55-
#define USE_FINAL_FS 0
56-
#endif
23+
#include "stdfs_conditions.h"
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#endif
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#if USE_FINAL_FS == 1

‎src/common/stdfs_conditions.h‎

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// Copyright (c) 2017-2021 The Khronos Group Inc.
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// Copyright (c) 2017 Valve Corporation
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// Copyright (c) 2017 LunarG, Inc.
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//
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// SPDX-License-Identifier: Apache-2.0 OR MIT
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7+
#ifndef _STDFS_CONDITIONS_H
8+
#define _STDFS_CONDITIONS_H
9+
10+
// If the C++ macro is set to the version containing C++17, it must support
11+
// the final C++17 package
12+
#if __cplusplus >= 201703L
13+
#define USE_EXPERIMENTAL_FS 0
14+
#define USE_FINAL_FS 1
15+
16+
#elif defined(_MSC_VER) && _MSC_VER >= 1900
17+
18+
#if defined(_HAS_CXX17) && _HAS_CXX17
19+
// When MSC supports c++17 use <filesystem> package.
20+
#define USE_EXPERIMENTAL_FS 0
21+
#define USE_FINAL_FS 1
22+
#endif // !_HAS_CXX17
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24+
// GCC supports the experimental filesystem items starting in GCC 6
25+
#elif (__GNUC__ >= 6)
26+
#define USE_EXPERIMENTAL_FS 1
27+
#define USE_FINAL_FS 0
28+
29+
// If Clang, check for feature support
30+
#elif defined(__clang__) && (__cpp_lib_filesystem || __cpp_lib_experimental_filesystem)
31+
#if __cpp_lib_filesystem
32+
#define USE_EXPERIMENTAL_FS 0
33+
#define USE_FINAL_FS 1
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#else
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#define USE_EXPERIMENTAL_FS 1
36+
#define USE_FINAL_FS 0
37+
#endif
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39+
// If all above fails, fall back to standard C++ and OS-specific items
40+
#else
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#define USE_EXPERIMENTAL_FS 0
42+
#define USE_FINAL_FS 0
43+
#endif
44+
45+
#endif // !_STDFS_CONDITIONS_H

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