From 027dac0358de7d07f772c32cbdf2306dfeae714b Mon Sep 17 00:00:00 2001
From: vrouvrea <vrouvrea@636b058d-ea47-450e-bf9e-a15bfbe3eedb>
Date: Wed, 6 Jun 2018 22:00:46 +0000
Subject: Merge of branch thread_local_optional_vincent to take into account
 XCode < v.8 as thread local is not available

git-svn-id: svn+ssh://scm.gforge.inria.fr/svnroot/gudhi/trunk@3554 636b058d-ea47-450e-bf9e-a15bfbe3eedb

Former-commit-id: 9dcf072a4606d1131a925bca4571f0f1b5547d14
---
 src/cmake/modules/GUDHI_compilation_flags.cmake | 49 ++++++++++++++++++++++---
 1 file changed, 43 insertions(+), 6 deletions(-)

(limited to 'src/cmake/modules')

diff --git a/src/cmake/modules/GUDHI_compilation_flags.cmake b/src/cmake/modules/GUDHI_compilation_flags.cmake
index 394f1f42..a01d6e13 100644
--- a/src/cmake/modules/GUDHI_compilation_flags.cmake
+++ b/src/cmake/modules/GUDHI_compilation_flags.cmake
@@ -1,6 +1,7 @@
 # This files manage compilation flags required by GUDHI
 
 include(TestCXXAcceptsFlag)
+include(CheckCXXSourceCompiles)
 
 # add a compiler flag only if it is accepted
 macro(add_cxx_compiler_flag _flag)
@@ -11,6 +12,32 @@ macro(add_cxx_compiler_flag _flag)
   endif()
 endmacro()
 
+function(can_cgal_use_cxx11_thread_local)
+  # This is because of https://github.com/CGAL/cgal/blob/master/Installation/include/CGAL/tss.h
+  # CGAL is using boost thread if thread_local is not ready (requires XCode 8 for Mac).
+  # The test in https://github.com/CGAL/cgal/blob/master/Installation/include/CGAL/config.h
+  #   #if __has_feature(cxx_thread_local) || \
+  #       ( (__GNUC__ * 100 + __GNUC_MINOR__) >= 408 && __cplusplus >= 201103L ) || \
+  #       ( _MSC_VER >= 1900 )
+  #   #define CGAL_CAN_USE_CXX11_THREAD_LOCAL
+  #   #endif
+  set(CGAL_CAN_USE_CXX11_THREAD_LOCAL "
+      int main() {
+      #ifndef __has_feature
+        #define __has_feature(x) 0  // Compatibility with non-clang compilers.
+      #endif
+      #if __has_feature(cxx_thread_local) || \
+          ( (__GNUC__ * 100 + __GNUC_MINOR__) >= 408 && __cplusplus >= 201103L ) || \
+          ( _MSC_VER >= 1900 )
+        bool has_feature_thread_local = true;
+      #else
+        // Explicit error of compilation for CMake test purpose - has_feature_thread_local is not defined
+      #endif
+        bool result = has_feature_thread_local;
+      }  ")
+  check_cxx_source_compiles("${CGAL_CAN_USE_CXX11_THREAD_LOCAL}" CGAL_CAN_USE_CXX11_THREAD_LOCAL_RESULT)
+endfunction()
+
 set (CMAKE_CXX_STANDARD 11)
 
 enable_testing()
@@ -22,14 +49,24 @@ endif()
 
 add_cxx_compiler_flag("-Wall")
 
-if(CMAKE_BUILD_TYPE MATCHES Debug)
-  message("++ Debug compilation flags are: ${CMAKE_CXX_FLAGS} ${CMAKE_CXX_FLAGS_DEBUG}")
-else()
-  message("++ Release compilation flags are: ${CMAKE_CXX_FLAGS} ${CMAKE_CXX_FLAGS_RELEASE}")
-endif()
-
 if (DEBUG_TRACES)
   # For programs to be more verbose
   message(STATUS "DEBUG_TRACES are activated")
   add_definitions(-DDEBUG_TRACES)
 endif()
+
+set(GUDHI_CAN_USE_CXX11_THREAD_LOCAL "
+    int main() {
+      thread_local int result = 0;
+      return result;
+    }  ")
+check_cxx_source_compiles("${GUDHI_CAN_USE_CXX11_THREAD_LOCAL}" GUDHI_CAN_USE_CXX11_THREAD_LOCAL_RESULT)
+if (GUDHI_CAN_USE_CXX11_THREAD_LOCAL_RESULT)
+  add_definitions(-DGUDHI_CAN_USE_CXX11_THREAD_LOCAL)
+endif()
+
+if(CMAKE_BUILD_TYPE MATCHES Debug)
+  message("++ Debug compilation flags are: ${CMAKE_CXX_FLAGS} ${CMAKE_CXX_FLAGS_DEBUG}")
+else()
+  message("++ Release compilation flags are: ${CMAKE_CXX_FLAGS} ${CMAKE_CXX_FLAGS_RELEASE}")
+endif()
-- 
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