Allow selection of system default C++ version.
This leaves the decision of which C++ version to use up to our users. We still have a static_assert in port_def.inc that will prevent pre-C++14 usage.
PiperOrigin-RevId: 501351066
diff --git a/CMakeLists.txt b/CMakeLists.txt
index f60142b..ab6a763 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -40,27 +40,6 @@
get_filename_component(protobuf_SOURCE_DIR ${protobuf_SOURCE_DIR} DIRECTORY)
endif()
-# Add C++14 flags
-if(NOT CMAKE_CXX_STANDARD)
- set(CMAKE_CXX_STANDARD 14)
-endif()
-if(CYGWIN)
- string(REGEX_MATCH "-std=gnu\\+\\+([0-9]+)" _protobuf_CXX_STD "${CMAKE_CXX_FLAGS}")
-endif()
-if(NOT _protobuf_CXX_STD)
- set(_protobuf_CXX_STD "${CMAKE_CXX_STANDARD}")
-endif()
-if(_protobuf_CXX_STD LESS "14")
- message(FATAL_ERROR "Protocol Buffers requires at least C++14, but is configured for C++${_protobuf_CXX_STD}")
-endif()
-if(CYGWIN)
- set(CMAKE_CXX_FLAGS "${CMAKE_CXX_FLAGS} -std=gnu++${_protobuf_CXX_STD}")
-else()
- set(CMAKE_CXX_STANDARD ${_protobuf_CXX_STD})
- set(CMAKE_CXX_STANDARD_REQUIRED ON)
- set(CMAKE_CXX_EXTENSIONS OFF)
-endif()
-
# The Intel compiler isn't able to deal with noinline member functions of
# template classes defined in headers. As such it spams the output with
# warning #2196: routine is both "inline" and "noinline"
diff --git a/cmake/README.md b/cmake/README.md
index 396d495..4bb2e05 100644
--- a/cmake/README.md
+++ b/cmake/README.md
@@ -8,6 +8,19 @@
Most of the instructions will be given using CMake's command-line interface, but
the same actions can be performed using appropriate GUI tools.
+# CMake Flags
+
+## C++ Version
+
+By default, CMake will use whatever C++ version is the system default. Since
+protobuf requires C++14 or newer, sometimes you will need to explicitly override
+this. For example, the following:
+
+ cmake . -DCMAKE_CXX_STANDARD=14
+ cmake --build
+
+will build protobuf using C++14 (see [CXX_STANDARD](https://cmake.org/cmake/help/latest/prop_tgt/CXX_STANDARD.html#prop_tgt:CXX_STANDARD){.external} for all available options).
+
# Windows Builds
On Windows, you can build the project from *Command Prompt* and using an
diff --git a/kokoro/common/cmake.sh b/kokoro/common/cmake.sh
index 99be3be..934170b 100755
--- a/kokoro/common/cmake.sh
+++ b/kokoro/common/cmake.sh
@@ -60,7 +60,8 @@
caplog 01_configure \
cmake -S "${SOURCE_DIR}" \
${CMAKE_BUILD_TYPE_FLAG} \
- ${CAPLOG_CMAKE_ARGS:-}
+ ${CAPLOG_CMAKE_ARGS:-} \
+ -DCMAKE_CXX_STANDARD=14
)
if [[ -n ${CAPLOG_DIR:-} ]]; then
# Save configuration logs.
diff --git a/kokoro/linux/32-bit/test_php.sh b/kokoro/linux/32-bit/test_php.sh
index 250e9ad..ef97337 100644
--- a/kokoro/linux/32-bit/test_php.sh
+++ b/kokoro/linux/32-bit/test_php.sh
@@ -38,7 +38,7 @@
mkdir -p build
pushd build
-cmake ..
+cmake .. -DCMAKE_CXX_STANDARD=14
cmake --build . -- -j20
ctest --verbose --parallel 20
export PROTOC=$(pwd)/protoc
diff --git a/kokoro/linux/cmake/build.sh b/kokoro/linux/cmake/build.sh
index 5abe392..67aea1b 100755
--- a/kokoro/linux/cmake/build.sh
+++ b/kokoro/linux/cmake/build.sh
@@ -8,7 +8,7 @@
cd $(dirname $0)/../../..
GIT_REPO_ROOT=`pwd`
-CONTAINER_IMAGE=gcr.io/protobuf-build/cmake/linux@sha256:79e6ed9d7f3f8e56167a3309a521e5b7e6a212bfb19855c65ee1cbb6f9099671
+CONTAINER_IMAGE=gcr.io/protobuf-build/cmake/linux@sha256:bd17c13255c8c7af2821c6597ad96568d714c0ea9d9e27d81b108fcc195ca858
# Update git submodules and regenerate files
git submodule update --init --recursive
@@ -22,7 +22,10 @@
--cidfile $tmpfile \
-v $GIT_REPO_ROOT:/workspace \
$CONTAINER_IMAGE \
- /test.sh -Dprotobuf_BUILD_CONFORMANCE=ON -Dprotobuf_BUILD_EXAMPLES=ON
+ /test.sh \
+ -Dprotobuf_BUILD_CONFORMANCE=ON \
+ -Dprotobuf_BUILD_EXAMPLES=ON \
+ -DCMAKE_CXX_STANDARD=14
# Save logs for Kokoro
docker cp \
diff --git a/kokoro/linux/cmake_install/build.sh b/kokoro/linux/cmake_install/build.sh
index 9efc110..bdd7ae6 100755
--- a/kokoro/linux/cmake_install/build.sh
+++ b/kokoro/linux/cmake_install/build.sh
@@ -8,7 +8,7 @@
cd $(dirname $0)/../../..
GIT_REPO_ROOT=`pwd`
-CONTAINER_IMAGE=gcr.io/protobuf-build/cmake/linux@sha256:79e6ed9d7f3f8e56167a3309a521e5b7e6a212bfb19855c65ee1cbb6f9099671
+CONTAINER_IMAGE=gcr.io/protobuf-build/cmake/linux@sha256:bd17c13255c8c7af2821c6597ad96568d714c0ea9d9e27d81b108fcc195ca858
# Update git submodules and regenerate files
git submodule update --init --recursive
@@ -22,10 +22,11 @@
--cidfile $tmpfile \
-v $GIT_REPO_ROOT:/workspace \
$CONTAINER_IMAGE \
- "/install.sh && /test.sh \
- -Dprotobuf_REMOVE_INSTALLED_HEADERS=ON \
- -Dprotobuf_BUILD_PROTOBUF_BINARIES=OFF \
- -Dprotobuf_BUILD_CONFORMANCE=ON"
+ "/install.sh -DCMAKE_CXX_STANDARD=14 && /test.sh \
+ -Dprotobuf_REMOVE_INSTALLED_HEADERS=ON \
+ -Dprotobuf_BUILD_PROTOBUF_BINARIES=OFF \
+ -Dprotobuf_BUILD_CONFORMANCE=ON \
+ -DCMAKE_CXX_STANDARD=14"
# Save logs for Kokoro
diff --git a/kokoro/linux/cmake_ninja/build.sh b/kokoro/linux/cmake_ninja/build.sh
index 133d97b..6ee3c61 100755
--- a/kokoro/linux/cmake_ninja/build.sh
+++ b/kokoro/linux/cmake_ninja/build.sh
@@ -8,7 +8,7 @@
cd $(dirname $0)/../../..
GIT_REPO_ROOT=`pwd`
-CONTAINER_IMAGE=gcr.io/protobuf-build/cmake/linux@sha256:79e6ed9d7f3f8e56167a3309a521e5b7e6a212bfb19855c65ee1cbb6f9099671
+CONTAINER_IMAGE=gcr.io/protobuf-build/cmake/linux@sha256:bd17c13255c8c7af2821c6597ad96568d714c0ea9d9e27d81b108fcc195ca858
# Update git submodules and regenerate files
git submodule update --init --recursive
@@ -22,7 +22,7 @@
--cidfile $tmpfile \
-v $GIT_REPO_ROOT:/workspace \
$CONTAINER_IMAGE \
- /test.sh -G Ninja -Dprotobuf_BUILD_CONFORMANCE=ON
+ /test.sh -G Ninja -Dprotobuf_BUILD_CONFORMANCE=ON -DCMAKE_CXX_STANDARD=14
# Save logs for Kokoro
docker cp \
diff --git a/kokoro/linux/cmake_shared/build.sh b/kokoro/linux/cmake_shared/build.sh
index f3d7534..2236926 100755
--- a/kokoro/linux/cmake_shared/build.sh
+++ b/kokoro/linux/cmake_shared/build.sh
@@ -8,7 +8,7 @@
cd $(dirname $0)/../../..
GIT_REPO_ROOT=`pwd`
-CONTAINER_IMAGE=gcr.io/protobuf-build/cmake/linux@sha256:79e6ed9d7f3f8e56167a3309a521e5b7e6a212bfb19855c65ee1cbb6f9099671
+CONTAINER_IMAGE=gcr.io/protobuf-build/cmake/linux@sha256:bd17c13255c8c7af2821c6597ad96568d714c0ea9d9e27d81b108fcc195ca858
# Update git submodules and regenerate files
git submodule update --init --recursive
@@ -22,7 +22,10 @@
--cidfile $tmpfile \
-v $GIT_REPO_ROOT:/workspace \
$CONTAINER_IMAGE \
- /test.sh -Dprotobuf_BUILD_CONFORMANCE=ON -Dprotobuf_BUILD_SHARED_LIBS=ON
+ /test.sh \
+ -Dprotobuf_BUILD_CONFORMANCE=ON \
+ -Dprotobuf_BUILD_SHARED_LIBS=ON \
+ -DCMAKE_CXX_STANDARD=14
# Save logs for Kokoro
docker cp \
