From: David Wells Date: Mon, 29 Jun 2015 03:11:55 +0000 (-0400) Subject: Re-enable automatic detection of C++ versions. X-Git-Tag: v8.3.0-rc1~83^2~1 X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=454625c7179353ca96c5ea5286fb7f18229cd454;p=dealii.git Re-enable automatic detection of C++ versions. I mistakenly removed this when adding C++14 support. --- diff --git a/cmake/checks/check_01_cxx_features.cmake b/cmake/checks/check_01_cxx_features.cmake index 7884c45a10..0170ce92a6 100644 --- a/cmake/checks/check_01_cxx_features.cmake +++ b/cmake/checks/check_01_cxx_features.cmake @@ -55,33 +55,62 @@ IF(DEAL_II_WITH_CXX14 AND DEFINED DEAL_II_WITH_CXX11 AND NOT DEAL_II_WITH_CXX11) ENDIF() # -# Only run these tests if C++11 support (or newer) should actually be set up: +# Test for C++11 flag support if the compiler supports a C++11 flag and C++11 +# support is not explicitly disabled. # -IF(DEAL_II_WITH_CXX11 OR DEAL_II_WITH_CXX14) - IF(NOT DEAL_II_CXX_VERSION_FLAG) - IF(DEAL_II_WITH_CXX14) - CHECK_CXX_COMPILER_FLAG("-std=c++14" DEAL_II_HAVE_FLAG_stdcxx14) - IF(DEAL_II_HAVE_FLAG_stdcxx14) - SET(DEAL_II_CXX_VERSION_FLAG "-std=c++14") - ELSE() - MESSAGE(FATAL_ERROR - "CMake was not able to find a valid C++14 flag. Try manually" - " specifying\nDEAL_II_CXX_VERSION_FLAG\nand reruning CMake.") - ENDIF() - ELSEIF(DEAL_II_WITH_CXX11) - CHECK_CXX_COMPILER_FLAG("-std=c++0x" DEAL_II_HAVE_FLAG_stdcxx0x) - CHECK_CXX_COMPILER_FLAG("-std=c++11" DEAL_II_HAVE_FLAG_stdcxx11) - IF(DEAL_II_HAVE_FLAG_stdcxx11) - SET(DEAL_II_CXX_VERSION_FLAG "-std=c++11") - ELSEIF(DEAL_II_HAVE_FLAG_stdcxx0x) - SET(DEAL_II_CXX_VERSION_FLAG "-std=c++0x") - ELSE() +IF((NOT DEFINED DEAL_II_WITH_CXX11 OR DEAL_II_WITH_CXX11) + AND NOT DEFINED DEAL_II_CXX_VERSION_FLAG) + CHECK_CXX_COMPILER_FLAG("-std=c++0x" DEAL_II_HAVE_FLAG_stdcxx0x) + CHECK_CXX_COMPILER_FLAG("-std=c++11" DEAL_II_HAVE_FLAG_stdcxx11) + IF(DEAL_II_HAVE_FLAG_stdcxx11) + SET(DEAL_II_CXX11_FLAG "-std=c++11") + ELSEIF(DEAL_II_HAVE_FLAG_stdcxx0x) + SET(DEAL_II_CXX11_FLAG "-std=c++0x") + ELSE() + IF(DEAL_II_WITH_CXX11) + MESSAGE(FATAL_ERROR + "C++11 support was requested but CMake was not able to find a valid C++11" + " flag. Try manually specifying DEAL_II_CXX_VERSION_FLAG and reruning CMake.") + ENDIF() + ENDIF() + + # + # C++11 support must not be explicitly disabled for C++14 support to be + # enabled. + # + + IF(NOT DEFINED DEAL_II_WITH_CXX14 OR DEAL_II_WITH_CXX14) + CHECK_CXX_COMPILER_FLAG("-std=c++1y" DEAL_II_HAVE_FLAG_stdcxx1y) + CHECK_CXX_COMPILER_FLAG("-std=c++14" DEAL_II_HAVE_FLAG_stdcxx14) + IF(DEAL_II_HAVE_FLAG_stdcxx14) + SET(DEAL_II_CXX14_FLAG "-std=c++14") + ELSEIF(DEAL_II_HAVE_FLAG_stdcxx1y) + SET(DEAL_II_CXX14_FLAG "-std=c++1y") + ELSE() + IF(DEAL_II_WITH_CXX14) MESSAGE(FATAL_ERROR - "CMake was not able to find a valid C++11 flag. Try manually" - " specifying\nDEAL_II_CXX_VERSION_FLAG and reruning CMake.") + "C++14 support was requested but CMake was not able to find a valid C++14" + " flag. Try manually specifying DEAL_II_CXX_VERSION_FLAG and reruning CMake.") ENDIF() ENDIF() + ENDIF() +ENDIF() + +# +# Only run these tests if CMake should attempt to set up C++11 (or newer) +# support. +# +IF(DEFINED DEAL_II_CXX11_FLAG OR DEFINED DEAL_II_CXX14_FLAG + OR DEFINED DEAL_II_CXX_VERSION_FLAG) + IF(NOT DEFINED DEAL_II_CXX_VERSION_FLAG) + IF(DEFINED DEAL_II_CXX14_FLAG) + SET(DEAL_II_CXX_VERSION_FLAG ${DEAL_II_CXX14_FLAG}) + ELSEIF(DEFINED DEAL_II_CXX11_FLAG) + SET(DEAL_II_CXX_VERSION_FLAG ${DEAL_II_CXX11_FLAG}) + ELSE() + SET(DEAL_II_CXX_VERSION_FLAG " ") + ENDIF() ELSE() CHECK_CXX_COMPILER_FLAG(${DEAL_II_CXX_VERSION_FLAG} DEAL_II_CXX_VERSION_FLAG_VALID) IF(NOT DEAL_II_CXX_VERSION_FLAG_VALID) @@ -286,8 +315,7 @@ IF(DEAL_II_WITH_CXX11 OR DEAL_II_WITH_CXX14) " DEAL_II_HAVE_CXX14_MAKE_UNIQUE) IF( DEAL_II_HAVE_CXX11 AND - DEAL_II_HAVE_CXX14_MAKE_UNIQUE AND - DEAL_II_WITH_CXX14) + DEAL_II_HAVE_CXX14_MAKE_UNIQUE) SET(DEAL_II_HAVE_CXX14 TRUE) ENDIF() @@ -344,7 +372,7 @@ IF(DEAL_II_WITH_CXX14 AND NOT DEAL_II_HAVE_CXX14) "Please disable C++14 support, i.e. configure with\n" " -DDEAL_II_WITH_CXX14=FALSE,\n" "or use a different compiler, instead. (If the compiler flag for C++14 " - "support differs from \"-std=c++14\", a suitable " + "support differs from \"-std=c++14\" or \"-std=c++1y\", a suitable " "compiler flag has to be specified manually via\n" " -DDEAL_II_CXX_VERSION_FLAG=\"...\"\n\n" ) @@ -356,6 +384,7 @@ ENDIF() IF (DEAL_II_WITH_CXX14) ADD_FLAGS(DEAL_II_CXX_FLAGS "${DEAL_II_CXX_VERSION_FLAG}") + MESSAGE(STATUS "DEAL_II_WITH_CXX11 successfully set up") MESSAGE(STATUS "DEAL_II_WITH_CXX14 successfully set up") ELSEIF(DEAL_II_WITH_CXX11) ADD_FLAGS(DEAL_II_CXX_FLAGS "${DEAL_II_CXX_VERSION_FLAG}") diff --git a/doc/users/cmake.html b/doc/users/cmake.html index 40363835a0..1f4913a356 100644 --- a/doc/users/cmake.html +++ b/doc/users/cmake.html @@ -432,12 +432,20 @@ parameter_gui - builds and installs the 'parameter_gui' component by cmake variables that may be set to either ON or OFF. - By default, deal.II does not provide the compiler with - any C++ version flag. If - either DEAL_II_WITH_CXX11 or DEAL_II_WITH_CXX14 - is set to ON, then cmake will attempt to - determine both the level of compliance and the correct compiler flag for - the requested language standard. + By default, deal.II's CMake build scripts + will attempt to find the newest C++ version available by + checking which language version flags work with the detected compiler. For + example: if CMake detects GCC 5.1 or Clang + 3.6, deal.II will be compiled + in C++14 mode unless either C++14 + or C++11 is explicitly disabled. Another example: + if DEAL_II_WITH_CXX11=ON is passed to CMake, + then deal.II will check if the compiler supports enough + parts of the C++11 and + C++14 language standards. CMake will not fail in + this example just because the compiler does not support + C++14, but CMake will fail if the + compiler does not support enough of C++11. The remaining flags are set to ON if an external package is found or to OFF otherwise. By explicitly setting it to off