CMakeLists.txt: Enable use of C++17 on Apple systems

The stdlib on OSX 12 Monteray requires C++17 to compile. This change
tests for and conditionally enables C++17 support on Apple devices.
Other platforms remain unaffected.

diff --git a/CMakeLists.txt b/CMakeLists.txt
index d5469883e5ba12e1aaa78ef61df850846fee889f..b12f50c7304c81cb53b5c38a421cb1ea490279b8 100644 (file)
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -75,12 +75,15 @@ add_subdirectory(manual)
 #-------------------------------------------------------------------------------
 
 include(CheckCSourceCompiles)
+include(CheckCXXCompilerFlag)
 include(CheckCXXSourceCompiles)
 include(CMakePushCheckState)
 include(memaccess)
 
 find_package(PkgConfig)
 
+check_cxx_compiler_flag("-std=c++17" PV_HAVE_C++17)
+
 list(APPEND PKGDEPS glib-2.0>=2.28.0)
 
 # Try to find the prefered glibmm-2.4. If not found then add glibmm-2.68
@@ -166,7 +169,13 @@ find_package(Threads REQUIRED)
 # Helper for checking for atomics
 function(check_working_cxx_atomics varname additional_lib)
        cmake_push_check_state()
-       set(CMAKE_REQUIRED_FLAGS "-std=c++11")
+       # The OSX 12 (Monteray) stdlib requires C++17 to compile.
+       if(APPLE AND PV_HAVE_C++17)
+               message(STATUS "Using C++17 for OSX build")
+               set(CMAKE_REQUIRED_FLAGS "-std=c++17")
+       else()
+               set(CMAKE_REQUIRED_FLAGS "-std=c++11")
+       endif()
        set(CMAKE_REQUIRED_LIBRARIES "${additional_lib}")
        set(CMAKE_REQUIRED_QUIET 1)
        CHECK_CXX_SOURCE_COMPILES("
@@ -499,7 +508,14 @@ qt5_add_resources(pulseview_RESOURCES_RCC ${CMAKE_BINARY_DIR}/translations.qrc)
 add_definitions(-DQT_NO_KEYWORDS)
 add_definitions(-D__STDC_LIMIT_MACROS)
 add_definitions(-Wall -Wextra)
-add_definitions(-std=c++11)
+
+# The OSX 12 Monteray stdlib requires C++17 to compile.
+if(APPLE AND PV_HAVE_C++17)
+       add_definitions(-std=c++17)
+else()
+       add_definitions(-std=c++11)
+endif()
+
 add_definitions(-DBOOST_MATH_DISABLE_FLOAT128=1)
 if(WIN32)
        add_definitions(-Wa,-mbig-obj -O3)