fmtlegacy/support/cmake/cxx14.cmake
2018-02-11 07:32:22 -08:00

98 lines
2.9 KiB
CMake

# C++14 feature support detection
if (NOT FMT_USE_CPP14)
return()
endif ()
include(CheckCXXCompilerFlag)
if (FMT_USE_CPP14)
check_cxx_compiler_flag(-std=c++14 HAVE_STD_CPP14_FLAG)
if (HAVE_STD_CPP14_FLAG)
# Check if including cmath works with -std=c++14 and -O3.
# It may not in MinGW due to bug http://ehc.ac/p/mingw/bugs/2250/.
set(CMAKE_REQUIRED_FLAGS "-std=c++14 -O3")
check_cxx_source_compiles("
#include <cmath>
int main() {}" FMT_CPP14_CMATH)
# Check if including <unistd.h> works with -std=c++14.
# It may not in MinGW due to bug http://sourceforge.net/p/mingw/bugs/2024/.
check_cxx_source_compiles("
#include <unistd.h>
int main() {}" FMT_CPP14_UNISTD_H)
# Check if snprintf works with -std=c++14. It may not in MinGW.
check_cxx_source_compiles("
#include <stdio.h>
int main() {
char buffer[10];
snprintf(buffer, 10, \"foo\");
}" FMT_CPP14_SNPRINTF)
if (FMT_CPP14_CMATH AND FMT_CPP14_UNISTD_H AND FMT_CPP14_SNPRINTF)
set(CPP14_FLAG -std=c++14)
else ()
check_cxx_compiler_flag(-std=gnu++14 HAVE_STD_GNUPP14_FLAG)
if (HAVE_STD_CPP14_FLAG)
set(CPP14_FLAG -std=gnu++14)
endif ()
endif ()
set(CMAKE_REQUIRED_FLAGS )
else ()
check_cxx_compiler_flag(-std=c++1y HAVE_STD_CPP1Y_FLAG)
if (HAVE_STD_CPP1Y_FLAG)
set(CPP14_FLAG -std=c++1y)
else ()
# Fallback on c++11 if c++14 is not available.
check_cxx_compiler_flag(-std=c++11 HAVE_STD_CPP11_FLAG)
if (HAVE_STD_CPP11_FLAG)
set(CPP14_FLAG -std=c++11)
else ()
check_cxx_compiler_flag(-std=c++0x HAVE_STD_CPP0X_FLAG)
if (HAVE_STD_CPP0X_FLAG)
set(CPP14_FLAG -std=c++0x)
endif ()
endif ()
endif ()
endif ()
endif ()
if (CMAKE_CXX_STANDARD)
# Don't use -std compiler flag if CMAKE_CXX_STANDARD is specified.
set(CPP14_FLAG )
endif ()
message(STATUS "CPP14_FLAG: ${CPP14_FLAG}")
set(CMAKE_REQUIRED_FLAGS ${CPP14_FLAG})
# Check if variadic templates are working and not affected by GCC bug 39653:
# https://gcc.gnu.org/bugzilla/show_bug.cgi?id=39653
check_cxx_source_compiles("
template <class T, class ...Types>
struct S { typedef typename S<Types...>::type type; };
int main() {}" SUPPORTS_VARIADIC_TEMPLATES)
# Check if initializer lists are supported.
check_cxx_source_compiles("
#include <initializer_list>
int main() {}" SUPPORTS_INITIALIZER_LIST)
# Check if enum bases are available
check_cxx_source_compiles("
enum C : char {A};
int main() {}"
SUPPORTS_ENUM_BASE)
# Check if type traits are available
check_cxx_source_compiles("
#include <type_traits>
class C { void operator=(const C&); };
int main() { static_assert(!std::is_copy_assignable<C>::value, \"\"); }"
SUPPORTS_TYPE_TRAITS)
# Check if user-defined literals are available
check_cxx_source_compiles("
void operator\"\" _udl(long double);
int main() {}"
SUPPORTS_USER_DEFINED_LITERALS)
set(CMAKE_REQUIRED_FLAGS )