Merging in latest from upstream (HDFFV/hdf5:refs/heads/develop)

* commit '5ea58acf8a2bdf8ca19d4c86d9ef94fbc4ac449f':
  Add missing ')'.
  Add C++ warnings treated as error for autotools builds.
  Move macro ADD_H5_CFLAGS to cmake_ext_mod/HDFMacros.cmake and remove duplicate versions.
  Address PR suggestions and add overlooked GCC compiler version flags.
  Don't add general warnings flags for unsupported old versions of gcc and g++ (older than gcc/g++ 4.2). Correct gnu-cxxflags to determine warnings flags to be added based on C++ compiler version instead of C compiler version.

9 files changed, 107 insertions, 104 deletions

diff --git a/config/cmake/HDFCXXCompilerFlags.cmake b/config/cmake/HDFCXXCompilerFlags.cmake
index 6aa8784..ec3b498 100644
--- a/config/cmake/HDFCXXCompilerFlags.cmake
+++ b/config/cmake/HDFCXXCompilerFlags.cmake
@@ -13,24 +13,6 @@ set(CMAKE_CXX_STANDARD 98)
 set(CMAKE_CXX_STANDARD_REQUIRED TRUE)
 set(CMAKE_CXX_EXTENSIONS OFF)
 
-macro (ADD_H5_FLAGS h5_flag_var infile)
-  file (STRINGS ${infile} TEST_FLAG_STREAM)
-  #message (STATUS "TEST_FLAG_STREAM=${TEST_FLAG_STREAM}")
-  list (LENGTH TEST_FLAG_STREAM len_flag)
-  if (len_flag GREATER 0)
-    math (EXPR _FP_LEN "${len_flag} - 1")
-    foreach (line RANGE 0 ${_FP_LEN})
-      list (GET TEST_FLAG_STREAM ${line} str_flag)
-      string (REGEX REPLACE "^#.*" "" str_flag "${str_flag}")
-      #message (STATUS "str_flag=${str_flag}")
-      if (str_flag)
-        list (APPEND ${h5_flag_var} "${str_flag}")
-      endif ()
-    endforeach ()
-  endif ()
-  #message (STATUS "h5_flag_var=${${h5_flag_var}}")
-endmacro ()
-
 set (CMAKE_CXX_FLAGS "${CMAKE_CXX_SANITIZER_FLAGS} ${CMAKE_CXX_FLAGS}")
 message (STATUS "Warnings Configuration: CXX default:  ${CMAKE_CXX_FLAGS}")
 #-----------------------------------------------------------------------------
@@ -103,10 +85,13 @@ if (NOT MSVC)
         list (APPEND H5_CXXFLAGS0 "-Wsign-compare -Wtrigraphs -Wwrite-strings")
       endif()
     elseif (CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
-      if (CMAKE_COMPILER_IS_GNUCXX AND CMAKE_CXX_COMPILER_LOADED)
-        # autotools always add the C flags with the CXX flags
+      if (CMAKE_COMPILER_IS_GNUCXX AND CMAKE_CXX_COMPILER_LOADED 
+          AND CMAKE_CXX_COMPILER_VERSION VERSION_GREATER_EQUAL 4.2)
+        # autotools adds the C flags with the CXX flags for g++ compiler 
+        # versions 4.2 and above.
         ADD_H5_FLAGS (HDF5_CMAKE_CXX_FLAGS "${HDF5_SOURCE_DIR}/config/gnu-warnings/general")
         ADD_H5_FLAGS (HDF5_CMAKE_CXX_FLAGS "${HDF5_SOURCE_DIR}/config/gnu-warnings/cxx-general")
+        ADD_H5_FLAGS (H5_CXXFLAGS0 "${HDF5_SOURCE_DIR}/config/gnu-warnings/error-general")
       endif ()
     elseif (CMAKE_CXX_COMPILER_ID STREQUAL "Clang")
       ADD_H5_FLAGS (HDF5_CMAKE_CXX_FLAGS "${HDF5_SOURCE_DIR}/config/clang-warnings/general")
@@ -141,17 +126,31 @@ if (NOT MSVC)
   endif ()
 
   if (CMAKE_CXX_COMPILER_ID STREQUAL "GNU")
-    # Append warning flags that only gcc 4.3+ knows about
-    # autotools always add the C flags with the CXX flags
-    ADD_H5_FLAGS (H5_CXXFLAGS1 "${HDF5_SOURCE_DIR}/config/gnu-warnings/4.3")
-    #
     # Technically, variable-length arrays are part of the C99 standard, but
     #   we should approach them a bit cautiously... Only needed for gcc 4.X
-    if (CMAKE_CXX_COMPILER_VERSION VERSION_LESS 5.0)
+    if (CMAKE_CXX_COMPILER_VERSION VERSION_LESS 5.0 AND CMAKE_C_COMPILER_VERSION VERSION_GREATER_EQUAL 4.2)
       # autotools always add the C flags with the CXX flags
       ADD_H5_FLAGS (H5_CXXFLAGS1 "${HDF5_SOURCE_DIR}/config/gnu-warnings/4.2-4.last")
     endif ()
 
+    # Append warning flags for gcc 4.2-4.3
+    # autotools always add the C flags with the CXX flags
+    if (CMAKE_C_COMPILER_VERSION VERSION_LESS_EQUAL 4.3 AND CMAKE_C_COMPILER_VERSION VERSION_GREATER_EQUAL 4.2)
+      ADD_H5_FLAGS (H5_CXXFLAGS1 "${HDF5_SOURCE_DIR}/config/gnu-warnings/4.2-4.3")
+    endif ()
+
+    # Append warning flags for gcc 4.2-4.4
+    # autotools always add the C flags with the CXX flags
+    if (CMAKE_C_COMPILER_VERSION VERSION_LESS_EQUAL 4.4 AND CMAKE_C_COMPILER_VERSION VERSION_GREATER_EQUAL 4.2)
+      ADD_H5_FLAGS (H5_CXXFLAGS1 "${HDF5_SOURCE_DIR}/config/gnu-warnings/4.2-4.4")
+    endif ()
+
+    # Append warning flags that only gcc 4.3+ knows about
+    # autotools always add the C flags with the CXX flags
+    if (CMAKE_C_COMPILER_VERSION VERSION_LESS 4.3 AND CMAKE_C_COMPILER_VERSION VERSION_GREATER_EQUAL 4.2)
+      ADD_H5_FLAGS (H5_CXXFLAGS1 "${HDF5_SOURCE_DIR}/config/gnu-warnings/4.3")
+    endif()
+
     # Append more extra warning flags that only gcc 4.4+ know about
     if (NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 4.4)
       # autotools always add the C flags with the CXX flags
@@ -172,7 +171,7 @@ if (NOT MSVC)
     endif ()
 
     # Append more extra warning flags that only gcc 4.6 and less know about
-    if (CMAKE_CXX_COMPILER_VERSION VERSION_LESS 4.7)
+    if (CMAKE_CXX_COMPILER_VERSION VERSION_LESS 4.7 AND CMAKE_C_COMPILER_VERSION VERSION_GREATER_EQUAL 4.2)
       # autotools always add the C flags with the CXX flags
       ADD_H5_FLAGS (H5_CXXFLAGS1 "${HDF5_SOURCE_DIR}/config/gnu-warnings/4.2-4.6")
     endif ()
@@ -255,6 +254,7 @@ if (NOT MSVC)
     if (NOT CMAKE_CXX_COMPILER_VERSION VERSION_LESS 8.0)
       # autotools always add the C flags with the CXX flags
       ADD_H5_FLAGS (H5_CXXFLAGS3 "${HDF5_SOURCE_DIR}/config/gnu-warnings/8")
+      ADD_H5_FLAGS (H5_CXXFLAGS3 "${HDF5_SOURCE_DIR}/config/gnu-warnings/error-8")
       if (HDF5_ENABLE_DEV_WARNINGS)
         # autotools always add the C flags with the CXX flags
         ADD_H5_FLAGS (H5_CXXFLAGS3 "${HDF5_SOURCE_DIR}/config/gnu-warnings/developer-8")
@@ -313,7 +313,7 @@ if (HDF5_ENABLE_GROUPZERO_WARNINGS)
   else ()
     if (CMAKE_COMPILER_IS_GNUCC)
       if (CMAKE_COMPILER_IS_GNUCXX AND CMAKE_CXX_COMPILER_LOADED)
-        list (APPEND HDF5_CMAKE_CXX_FLAGS ${H5_CFLAGS0})
+        list (APPEND HDF5_CMAKE_CXX_FLAGS ${H5_CXXFLAGS0})
       endif ()
     endif ()
   endif ()
@@ -332,7 +332,7 @@ if (HDF5_ENABLE_GROUPONE_WARNINGS)
   else ()
     if (CMAKE_COMPILER_IS_GNUCC)
       if (CMAKE_COMPILER_IS_GNUCXX AND CMAKE_CXX_COMPILER_LOADED)
-        list (APPEND HDF5_CMAKE_CXX_FLAGS ${H5_CFLAGS1})
+        list (APPEND HDF5_CMAKE_CXX_FLAGS ${H5_CXXFLAGS1})
       endif ()
     endif ()
   endif ()
@@ -351,7 +351,7 @@ if (HDF5_ENABLE_GROUPTWO_WARNINGS)
   else ()
     if (CMAKE_COMPILER_IS_GNUCC)
       if (CMAKE_COMPILER_IS_GNUCXX AND CMAKE_CXX_COMPILER_LOADED)
-        list (APPEND HDF5_CMAKE_CXX_FLAGS ${H5_CFLAGS2})
+        list (APPEND HDF5_CMAKE_CXX_FLAGS ${H5_CXXFLAGS2})
       endif ()
     endif ()
   endif ()
@@ -370,7 +370,7 @@ if (HDF5_ENABLE_GROUPTHREE_WARNINGS)
   else ()
     if (CMAKE_COMPILER_IS_GNUCC)
       if (CMAKE_COMPILER_IS_GNUCXX AND CMAKE_CXX_COMPILER_LOADED)
-        list (APPEND HDF5_CMAKE_CXX_FLAGS ${H5_CFLAGS3})
+        list (APPEND HDF5_CMAKE_CXX_FLAGS ${H5_CXXFLAGS3})
       endif ()
     endif ()
   endif ()
@@ -384,7 +384,7 @@ if (HDF5_ENABLE_GROUPFOUR_WARNINGS)
   if (NOT MSVC)
     if (CMAKE_COMPILER_IS_GNUCC)
       if (CMAKE_COMPILER_IS_GNUCXX AND CMAKE_CXX_COMPILER_LOADED)
-        list (APPEND HDF5_CMAKE_CXX_FLAGS ${H5_CFLAGS4})
+        list (APPEND HDF5_CMAKE_CXX_FLAGS ${H5_CXXFLAGS4})
       endif ()
     endif ()
   endif ()
diff --git a/config/cmake/HDFCompilerFlags.cmake b/config/cmake/HDFCompilerFlags.cmake
index 72141c0..02bc8b1 100644
--- a/config/cmake/HDFCompilerFlags.cmake
+++ b/config/cmake/HDFCompilerFlags.cmake
@@ -12,24 +12,6 @@
 set(CMAKE_C_STANDARD 99)
 set(CMAKE_C_STANDARD_REQUIRED TRUE)
 
-macro (ADD_H5_FLAGS h5_flag_var infile)
-  file (STRINGS ${infile} TEST_FLAG_STREAM)
-  #message (STATUS "TEST_FLAG_STREAM=${TEST_FLAG_STREAM}")
-  list (LENGTH TEST_FLAG_STREAM len_flag)
-  if (len_flag GREATER 0)
-    math (EXPR _FP_LEN "${len_flag} - 1")
-    foreach (line RANGE 0 ${_FP_LEN})
-      list (GET TEST_FLAG_STREAM ${line} str_flag)
-      string (REGEX REPLACE "^#.*" "" str_flag "${str_flag}")
-      #message (STATUS "str_flag=${str_flag}")
-      if (str_flag)
-        list (APPEND ${h5_flag_var} "${str_flag}")
-      endif ()
-    endforeach ()
-  endif ()
-  #message (STATUS "h5_flag_var=${${h5_flag_var}}")
-endmacro ()
-
 set (CMAKE_C_FLAGS "${CMAKE_C99_STANDARD_COMPILE_OPTION} ${CMAKE_C_FLAGS}")
 set (CMAKE_C_FLAGS "${CMAKE_C_SANITIZER_FLAGS} ${CMAKE_C_FLAGS}")
 set (CMAKE_CXX_FLAGS "${CMAKE_CXX_SANITIZER_FLAGS} ${CMAKE_CXX_FLAGS}")
@@ -111,8 +93,11 @@ if (NOT MSVC)
         list (APPEND H5_CFLAGS0 "-Wsign-compare -Wtrigraphs -Wwrite-strings")
       endif()
     elseif (CMAKE_C_COMPILER_ID STREQUAL "GNU")
-      ADD_H5_FLAGS (HDF5_CMAKE_C_FLAGS "${HDF5_SOURCE_DIR}/config/gnu-warnings/general")
-      ADD_H5_FLAGS (H5_CFLAGS0 "${HDF5_SOURCE_DIR}/config/gnu-warnings/error-general")
+      # Add general CFlags for GCC versions 4.2 and above
+      if (CMAKE_C_COMPILER_VERSION VERSION_GREATER_EQUAL 4.2)
+        ADD_H5_FLAGS (HDF5_CMAKE_C_FLAGS "${HDF5_SOURCE_DIR}/config/gnu-warnings/general")
+        ADD_H5_FLAGS (H5_CFLAGS0 "${HDF5_SOURCE_DIR}/config/gnu-warnings/error-general")
+      endif ()
       # gcc automatically inlines based on the optimization level
       # this is just a failsafe
       list (APPEND H5_CFLAGS0 "-finline-functions")
@@ -149,15 +134,27 @@ if (NOT MSVC)
 
 
   if (CMAKE_C_COMPILER_ID STREQUAL "GNU")
-    # Append warning flags that only gcc 4.3+ knows about
-    ADD_H5_FLAGS (H5_CFLAGS1 "${HDF5_SOURCE_DIR}/config/gnu-warnings/4.3")
-    #
     # Technically, variable-length arrays are part of the C99 standard, but
     #   we should approach them a bit cautiously... Only needed for gcc 4.X
-    if (CMAKE_C_COMPILER_VERSION VERSION_LESS 5.0)
+    if (CMAKE_C_COMPILER_VERSION VERSION_LESS 5.0 AND CMAKE_C_COMPILER_VERSION VERSION_GREATER_EQUAL 4.2)
       ADD_H5_FLAGS (H5_CFLAGS1 "${HDF5_SOURCE_DIR}/config/gnu-warnings/4.2-4.last")
     endif ()
 
+    # Append warning flags for gcc 4.2-4.3 
+    if (CMAKE_C_COMPILER_VERSION VERSION_LESS_EQUAL 4.3 AND CMAKE_C_COMPILER_VERSION VERSION_GREATER_EQUAL 4.2)
+      ADD_H5_FLAGS (H5_CFLAGS1 "${HDF5_SOURCE_DIR}/config/gnu-warnings/4.2-4.3")
+    endif ()
+
+    # Append warning flags for gcc 4.2-4.4 
+    if (CMAKE_C_COMPILER_VERSION VERSION_LESS_EQUAL 4.4 AND CMAKE_C_COMPILER_VERSION VERSION_GREATER_EQUAL 4.2)
+      ADD_H5_FLAGS (H5_CFLAGS1 "${HDF5_SOURCE_DIR}/config/gnu-warnings/4.2-4.4")
+    endif ()
+
+    # Append warning flags that only gcc 4.3+ knows about
+    if (NOT CMAKE_C_COMPILER_VERSION VERSION_LESS 4.3)
+      ADD_H5_FLAGS (H5_CFLAGS1 "${HDF5_SOURCE_DIR}/config/gnu-warnings/4.3")
+    endif ()
+
     # Append more extra warning flags that only gcc 4.4+ know about
     if (NOT CMAKE_C_COMPILER_VERSION VERSION_LESS 4.4)
       ADD_H5_FLAGS (H5_CFLAGS1 "${HDF5_SOURCE_DIR}/config/gnu-warnings/4.4")
@@ -174,7 +171,7 @@ if (NOT MSVC)
     endif ()
 
     # Append more extra warning flags that only gcc 4.6 and less know about
-    if (CMAKE_C_COMPILER_VERSION VERSION_LESS 4.7)
+    if (CMAKE_C_COMPILER_VERSION VERSION_LESS 4.7 AND CMAKE_C_COMPILER_VERSION VERSION_GREATER_EQUAL 4.2)
       ADD_H5_FLAGS (H5_CFLAGS1 "${HDF5_SOURCE_DIR}/config/gnu-warnings/4.2-4.6")
     endif ()
 
@@ -218,7 +215,7 @@ if (NOT MSVC)
       ADD_H5_FLAGS (H5_CFLAGS1 "${HDF5_SOURCE_DIR}/config/gnu-warnings/4.9")
     endif ()
 
-    # Append more extra warning flags that only gcc 5.1+ know about
+    # Append more extra warning flags that only gcc 5.x+ know about
     if (NOT CMAKE_C_COMPILER_VERSION VERSION_LESS 5.0)
       ADD_H5_FLAGS (H5_CFLAGS1 "${HDF5_SOURCE_DIR}/config/gnu-warnings/5")
       ADD_H5_FLAGS (H5_CFLAGS1 "${HDF5_SOURCE_DIR}/config/gnu-warnings/error-5")
@@ -242,6 +239,7 @@ if (NOT MSVC)
     # Append more extra warning flags that only gcc 8.x+ know about
     if (NOT CMAKE_C_COMPILER_VERSION VERSION_LESS 8.0)
       ADD_H5_FLAGS (H5_CFLAGS3 "${HDF5_SOURCE_DIR}/config/gnu-warnings/8")
+      ADD_H5_FLAGS (H5_CFLAGS3 "${HDF5_SOURCE_DIR}/config/gnu-warnings/error-8")
       if (HDF5_ENABLE_DEV_WARNINGS)
         ADD_H5_FLAGS (H5_CFLAGS3 "${HDF5_SOURCE_DIR}/config/gnu-warnings/developer-8")
       else ()
diff --git a/config/cmake/HDFFortranCompilerFlags.cmake b/config/cmake/HDFFortranCompilerFlags.cmake
index a56ef28..495a0ca 100644
--- a/config/cmake/HDFFortranCompilerFlags.cmake
+++ b/config/cmake/HDFFortranCompilerFlags.cmake
@@ -10,24 +10,6 @@
 # help@hdfgroup.org.
 #
 
-macro (ADD_H5_FFLAGS h5_fflag_var infile)
-  file (STRINGS ${infile} TEST_FLAG_STREAM)
-  #message (STATUS "TEST_FLAG_STREAM=${TEST_FLAG_STREAM}")
-  list (LENGTH TEST_FLAG_STREAM len_flag)
-  if (len_flag GREATER 0)
-    math (EXPR _FP_LEN "${len_flag} - 1")
-    foreach (line RANGE 0 ${_FP_LEN})
-      list (GET TEST_FLAG_STREAM ${line} str_flag)
-      string (REGEX REPLACE "^#.*" "" str_flag "${str_flag}")
-      #message (STATUS "str_flag=${str_flag}")
-      if (str_flag)
-        list (APPEND ${h5_fflag_var} "${str_flag}")
-      endif ()
-    endforeach ()
-  endif ()
-  #message (STATUS "h5_fflag_var=${${h5_fflag_var}}")
-endmacro ()
-
 message (STATUS "Warnings Configuration: default Fortran: ${CMAKE_Fortran_FLAGS}")
 
 #-----------------------------------------------------------------------------
diff --git a/config/cmake_ext_mod/HDFMacros.cmake b/config/cmake_ext_mod/HDFMacros.cmake
index fee6def..5740740 100644
--- a/config/cmake_ext_mod/HDFMacros.cmake
+++ b/config/cmake_ext_mod/HDFMacros.cmake
@@ -429,3 +429,21 @@ macro (HDF_DIR_PATHS package_prefix)
   endif ()
 endmacro ()
 
+macro (ADD_H5_FLAGS h5_flag_var infile)
+  file (STRINGS ${infile} TEST_FLAG_STREAM)
+  #message (STATUS "TEST_FLAG_STREAM=${TEST_FLAG_STREAM}")
+  list (LENGTH TEST_FLAG_STREAM len_flag)
+  if (len_flag GREATER 0)
+    math (EXPR _FP_LEN "${len_flag} - 1")
+    foreach (line RANGE 0 ${_FP_LEN})
+      list (GET TEST_FLAG_STREAM ${line} str_flag)
+      string (REGEX REPLACE "^#.*" "" str_flag "${str_flag}")
+      #message (STATUS "str_flag=${str_flag}")
+      if (str_flag)
+        list (APPEND ${h5_flag_var} "${str_flag}")
+      endif ()
+    endforeach ()
+  endif ()
+  #message (STATUS "h5_flag_var=${${h5_flag_var}}")
+endmacro ()
+
diff --git a/config/commence.am b/config/commence.am
index 41e0f3f..6e3d9a9 100644
--- a/config/commence.am
+++ b/config/commence.am
@@ -72,7 +72,7 @@ H5CPP=${DESTDIR}$(bindir)/h5c++
 
 AM_CFLAGS=@AM_CFLAGS@ @H5_CFLAGS@ @H5_ECFLAGS@
 AM_FCFLAGS=@AM_FCFLAGS@ @H5_FCFLAGS@
-AM_CXXFLAGS=@AM_CXXFLAGS@ @H5_CXXFLAGS@
+AM_CXXFLAGS=@AM_CXXFLAGS@ @H5_CXXFLAGS@ @H5_ECXXFLAGS@
 AM_CPPFLAGS=@AM_CPPFLAGS@ @H5_CPPFLAGS@
 AM_LDFLAGS=@AM_LDFLAGS@ @H5_LDFLAGS@
 
diff --git a/config/gnu-cxxflags b/config/gnu-cxxflags
index e177aef..b3b082d 100644
--- a/config/gnu-cxxflags
+++ b/config/gnu-cxxflags
@@ -79,9 +79,9 @@ if test "X-" = "X-$cxx_flags_set"; then
     cxx_vers_major=`echo $cxx_version | cut -f1 -d.`
     cxx_vers_minor=`echo $cxx_version | cut -f2 -d.`
     cxx_vers_patch=`echo $cxx_version | cut -f3 -d.`
-    test -n "$cc_vers_major" || cxx_vers_major=0
-    test -n "$cc_vers_minor" || cxx_vers_minor=0
-    test -n "$cc_vers_patch" || cxx_vers_patch=0
+    test -n "$cxx_vers_major" || cxx_vers_major=0
+    test -n "$cxx_vers_minor" || cxx_vers_minor=0
+    test -n "$cxx_vers_patch" || cxx_vers_patch=0
     cxx_vers_all=`expr $cxx_vers_major '*' 1000000 + $cxx_vers_minor '*' 1000 + $cxx_vers_patch`
 fi
 
@@ -180,10 +180,12 @@ if test "X-g++" = "X-$cxx_vendor"; then
     # General #
     ###########
 
-    H5_CXXFLAGS="$H5_CXXFLAGS $(load_gnu_arguments general)"
-    H5_ECXXFLAGS="$H5_ECXXFLAGS $(load_gnu_arguments error-general)"
-    H5_CXXFLAGS="$H5_CXXFLAGS $(load_gnu_arguments cxx-general)"
-    #H5_ECXXFLAGS="$H5_ECXXFLAGS $(load_gnu_arguments error-cxx-general)"
+    if test $cxx_vers_major -eq 4 -a $cxx_vers_minor -ge 2 -o $cxx_vers_major -gt 4; then
+        H5_CXXFLAGS="$H5_CXXFLAGS $(load_gnu_arguments general)"
+        H5_ECXXFLAGS="$H5_ECXXFLAGS $(load_gnu_arguments error-general)"
+        H5_CXXFLAGS="$H5_CXXFLAGS $(load_gnu_arguments cxx-general)"
+        #H5_ECXXFLAGS="$H5_ECXXFLAGS $(load_gnu_arguments error-cxx-general)"
+    fi
 
     ######################
     # Developer warnings #
@@ -197,27 +199,27 @@ if test "X-g++" = "X-$cxx_vendor"; then
     #######################
 
     # GCC 4.2 through 4.6
-    if test $cc_vers_major -eq 4 -a $cc_vers_minor -ge 2 -o $cc_vers_major -eq 4 -a $cc_vers_minor -le 6; then
+    if test $cxx_vers_major -eq 4 -a $cxx_vers_minor -ge 2 -o $cxx_vers_major -eq 4 -a $cxx_vers_minor -le 6; then
         H5_CXXFLAGS="$H5_CXXFLAGS $(load_gnu_arguments 4.2-4.6)"
     fi
 
     # GCC 4.2 through 4.3
-    if test $cc_vers_major -eq 4 -a $cc_vers_minor -ge 2 -o $cc_vers_major -eq 4 -a $cc_vers_minor -le 3; then
+    if test $cxx_vers_major -eq 4 -a $cxx_vers_minor -ge 2 -o $cxx_vers_major -eq 4 -a $cxx_vers_minor -le 3; then
         H5_CXXFLAGS="$H5_CXXFLAGS $(load_gnu_arguments 4.2-4.3)"
     fi
 
     # GCC 4.5 through 4.6
-    if test $cc_vers_major -eq 4 -a $cc_vers_minor -ge 5 -o $cc_vers_major -eq 4 -a $cc_vers_minor -le 6; then
+    if test $cxx_vers_major -eq 4 -a $cxx_vers_minor -ge 5 -o $cxx_vers_major -eq 4 -a $cxx_vers_minor -le 6; then
         H5_CXXFLAGS="$H5_CXXFLAGS $(load_gnu_arguments 4.5-4.6)"
     fi
 
     # GCC 4.2 through 4.4
-    if test $cc_vers_major -eq 4 -a $cc_vers_minor -ge 2 -a $cc_vers_major -eq 4 -a $cc_vers_minor -le 4; then
+    if test $cxx_vers_major -eq 4 -a $cxx_vers_minor -ge 2 -a $cxx_vers_major -eq 4 -a $cxx_vers_minor -le 4; then
         H5_CXXFLAGS="$H5_CXXFLAGS $(load_gnu_arguments 4.2-4.4)"
     fi
 
     # GCC 4.2 through the end of GCC 4 series
-    if test $cc_vers_major -eq 4 -a $cc_vers_minor -ge 2; then
+    if test $cxx_vers_major -eq 4 -a $cxx_vers_minor -ge 2; then
         H5_CXXFLAGS="$H5_CXXFLAGS $(load_gnu_arguments 4.2-4.last)"
     fi
 
@@ -226,68 +228,68 @@ if test "X-g++" = "X-$cxx_vendor"; then
     #############################
 
     # gcc >= 4.3
-    if test $cc_vers_major -ge 5 -o $cc_vers_major -eq 4 -a $cc_vers_minor -ge 3; then
+    if test $cxx_vers_major -ge 5 -o $cxx_vers_major -eq 4 -a $cxx_vers_minor -ge 3; then
         H5_CXXFLAGS="$H5_CXXFLAGS $(load_gnu_arguments 4.3)"
     fi
 
     # gcc >= 4.4
-    if test $cc_vers_major -ge 5 -o $cc_vers_major -eq 4 -a $cc_vers_minor -ge 4; then
+    if test $cxx_vers_major -ge 5 -o $cxx_vers_major -eq 4 -a $cxx_vers_minor -ge 4; then
         H5_CXXFLAGS="$H5_CXXFLAGS $(load_gnu_arguments 4.4)"
     fi
 
     # gcc >= 4.5
-    if test $cc_vers_major -ge 5 -o $cc_vers_major -eq 4 -a $cc_vers_minor -ge 5; then
+    if test $cxx_vers_major -ge 5 -o $cxx_vers_major -eq 4 -a $cxx_vers_minor -ge 5; then
         H5_CXXFLAGS="$H5_CXXFLAGS $(load_gnu_arguments 4.5)"
     DEVELOPER_WARNING_CXXFLAGS="$DEVELOPER_WARNING_CXXFLAGS $(load_gnu_arguments developer-4.5)"
     NO_DEVELOPER_WARNING_CXXFLAGS="$NO_DEVELOPER_WARNING_CXXFLAGS $(load_gnu_arguments no-developer-4.5)"
     fi
 
     # gcc >= 4.6
-    if test $cc_vers_major -ge 5 -o $cc_vers_major -eq 4 -a $cc_vers_minor -ge 6; then
+    if test $cxx_vers_major -ge 5 -o $cxx_vers_major -eq 4 -a $cxx_vers_minor -ge 6; then
         H5_CXXFLAGS="$H5_CXXFLAGS $(load_gnu_arguments 4.6)"
     DEVELOPER_WARNING_CXXFLAGS="$DEVELOPER_WARNING_CXXFLAGS $(load_gnu_arguments developer-4.6)"
     NO_DEVELOPER_WARNING_CXXFLAGS="$NO_DEVELOPER_WARNING_CXXFLAGS $(load_gnu_arguments no-developer-4.6)"
     fi
 
     # gcc >= 4.7
-    if test $cc_vers_major -ge 5 -o $cc_vers_major -eq 4 -a $cc_vers_minor -ge 7; then
+    if test $cxx_vers_major -ge 5 -o $cxx_vers_major -eq 4 -a $cxx_vers_minor -ge 7; then
         H5_CXXFLAGS="$H5_CXXFLAGS $(load_gnu_arguments 4.7)"
     DEVELOPER_WARNING_CXXFLAGS="$DEVELOPER_WARNING_CXXFLAGS $(load_gnu_arguments developer-4.7)"
     NO_DEVELOPER_WARNING_CXXFLAGS="$NO_DEVELOPER_WARNING_CXXFLAGS $(load_gnu_arguments no-developer-4.7)"
     fi
 
     # gcc >= 4.8
-    if test $cc_vers_major -ge 5 -o $cc_vers_major -eq 4 -a $cc_vers_minor -ge 8; then
+    if test $cxx_vers_major -ge 5 -o $cxx_vers_major -eq 4 -a $cxx_vers_minor -ge 8; then
         H5_CXXFLAGS="$H5_CXXFLAGS $(load_gnu_arguments 4.8)"
     DEVELOPER_WARNING_CXXFLAGS="$DEVELOPER_WARNING_CXXFLAGS $(load_gnu_arguments developer-4.8)"
     NO_DEVELOPER_WARNING_CXXFLAGS="$NO_DEVELOPER_WARNING_CXXFLAGS $(load_gnu_arguments no-developer-4.8)"
     fi
 
     # gcc >= 4.9
-    if test $cc_vers_major -ge 5 -o $cc_vers_major -eq 4 -a $cc_vers_minor -ge 9; then
+    if test $cxx_vers_major -ge 5 -o $cxx_vers_major -eq 4 -a $cxx_vers_minor -ge 9; then
         H5_CXXFLAGS="$H5_CXXFLAGS $(load_gnu_arguments 4.9)"
         H5_CXXFLAGS="$H5_CXXFLAGS $(load_gnu_arguments cxx-4.9)"
     fi
 
     # gcc >= 5
-    if test $cc_vers_major -ge 5; then
+    if test $cxx_vers_major -ge 5; then
         H5_CXXFLAGS="$H5_CXXFLAGS $(load_gnu_arguments 5)"
         H5_ECXXFLAGS="$H5_ECXXFLAGS $(load_gnu_arguments error-5)"
     fi
 
     # gcc >= 6
-    if test $cc_vers_major -ge 6; then
+    if test $cxx_vers_major -ge 6; then
         H5_CXXFLAGS="$H5_CXXFLAGS $(load_gnu_arguments 6)"
     fi
 
     # gcc >= 7
-    if test $cc_vers_major -ge 7; then
+    if test $cxx_vers_major -ge 7; then
         H5_CXXFLAGS="$H5_CXXFLAGS $(load_gnu_arguments 7)"
     DEVELOPER_WARNING_CXXFLAGS="$DEVELOPER_WARNING_CXXFLAGS $(load_gnu_arguments developer-7)"
     fi
 
     # gcc 8
-    if test $cc_vers_major -ge 8; then
+    if test $cxx_vers_major -ge 8; then
         H5_CXXFLAGS="$H5_CXXFLAGS $(load_gnu_arguments 8)"
         H5_ECXXFLAGS="$H5_ECXXFLAGS $(load_gnu_arguments error-8)"
     DEVELOPER_WARNING_CXXFLAGS="$DEVELOPER_WARNING_CXXFLAGS $(load_gnu_arguments developer-8)"
@@ -295,7 +297,7 @@ if test "X-g++" = "X-$cxx_vendor"; then
     fi
 
     # gcc 9
-    if test $cc_vers_major -ge 9; then
+    if test $cxx_vers_major -ge 9; then
         H5_CXXFLAGS="$H5_CXXFLAGS $(load_gnu_arguments 9)"
     fi
 
diff --git a/config/gnu-flags b/config/gnu-flags
index ad07552..dba9324 100644
--- a/config/gnu-flags
+++ b/config/gnu-flags
@@ -188,8 +188,10 @@ if test "X-gcc" = "X-$cc_vendor"; then
     # General #
     ###########
 
-    H5_CFLAGS="$H5_CFLAGS $(load_gnu_arguments general)"
-    H5_ECFLAGS="$H5_ECFLAGS $(load_gnu_arguments error-general)"
+    if test $cc_vers_major -eq 4 -a $cc_vers_minor -ge 2 -o $cc_vers_major -gt 4; then
+        H5_CFLAGS="$H5_CFLAGS $(load_gnu_arguments general)"
+        H5_ECFLAGS="$H5_ECFLAGS $(load_gnu_arguments error-general)"
+    fi
 
     ######################
     # Developer warnings #
diff --git a/configure.ac b/configure.ac
index 81e985e..db0cddf 100644
--- a/configure.ac
+++ b/configure.ac
@@ -104,13 +104,14 @@ AC_SUBST([AR_FLAGS])
 ## H5_CFLAGS (and company) are for CFLAGS that should be used on HDF5, but
 ## not exported to h5cc (or h5fc, etc.)
 ##
-## H5_ECFLAGS is for warnings that should be treated as errors.
+## H5_ECFLAGS (and company) are for warnings that should be treated as errors.
 ##
 AC_SUBST([H5_CFLAGS])
 AC_SUBST([H5_ECFLAGS])
 AC_SUBST([H5_CPPFLAGS])
 AC_SUBST([H5_FCFLAGS])
 AC_SUBST([H5_CXXFLAGS])
+AC_SUBST([H5_ECXXFLAGS])
 AC_SUBST([H5_JNIFLAGS])
 AC_SUBST([H5_JAVACFLAGS])
 AC_SUBST([H5_JAVAFLAGS])
diff --git a/src/libhdf5.settings.in b/src/libhdf5.settings.in
index 192fc6f..fb9deec 100644
--- a/src/libhdf5.settings.in
+++ b/src/libhdf5.settings.in
@@ -56,7 +56,7 @@ Languages:
                             C++: @HDF_CXX@
 @BUILD_CXX_CONDITIONAL_TRUE@                   C++ Compiler: @CXX_VERSION@
 @BUILD_CXX_CONDITIONAL_TRUE@                      C++ Flags: @CXXFLAGS@
-@BUILD_CXX_CONDITIONAL_TRUE@                   H5 C++ Flags: @H5_CXXFLAGS@
+@BUILD_CXX_CONDITIONAL_TRUE@                   H5 C++ Flags: @H5_CXXFLAGS@ @H5_ECXXFLAGS@
 @BUILD_CXX_CONDITIONAL_TRUE@                   AM C++ Flags: @AM_CXXFLAGS@
 @BUILD_CXX_CONDITIONAL_TRUE@             Shared C++ Library: @enable_shared@
 @BUILD_CXX_CONDITIONAL_TRUE@             Static C++ Library: @enable_static@