Corrects more Fortran warnings (#2059)

* Moves -Wunused-dummy-arguments to the developer warnings since this
  generates a lot of spurious, unfixable noise due to things like
  callback wrappers
* Changes the return cast in h5fget_fileno_c, fixes a comment, and comment
  on potential badness
* Initializes a variable in tH5L_F03.F90 to quiet a 'maybe
  uninitialized' warning

5 files changed, 16 insertions, 6 deletions

diff --git a/config/cmake/HDFFortranCompilerFlags.cmake b/config/cmake/HDFFortranCompilerFlags.cmake
index 13e9902..7fdc3f8 100644
--- a/config/cmake/HDFFortranCompilerFlags.cmake
+++ b/config/cmake/HDFFortranCompilerFlags.cmake
@@ -54,10 +54,6 @@ if (CMAKE_Fortran_COMPILER_ID STREQUAL "GNU" AND NOT CMAKE_Fortran_COMPILER_VERS
   endif ()
 endif ()
 
-#-----------------------------------------------------------------------------
-# CDash is configured to only allow 3000 warnings, so
-# break into groups (from the config/gnu-flags file)
-#-----------------------------------------------------------------------------
 if (NOT MSVC AND NOT MINGW)
   # General flags
   if (CMAKE_Fortran_COMPILER_ID STREQUAL "Intel")
@@ -65,6 +61,11 @@ if (NOT MSVC AND NOT MINGW)
     list (APPEND HDF5_CMAKE_Fortran_FLAGS "-free")
   elseif (CMAKE_Fortran_COMPILER_ID STREQUAL "GNU")
     ADD_H5_FLAGS (HDF5_CMAKE_Fortran_FLAGS "${HDF5_SOURCE_DIR}/config/gnu-warnings/gfort-general")
+    if (HDF5_ENABLE_DEV_WARNINGS)
+      ADD_H5_FLAGS (HDF5_CMAKE_Fortran_FLAGS "${HDF5_SOURCE_DIR}/config/gnu-warnings/gfort-developer-general")
+    else ()
+      ADD_H5_FLAGS (HDF5_CMAKE_Fortran_FLAGS "${HDF5_SOURCE_DIR}/config/gnu-warnings/gfort-no-developer-general")
+    endif ()
     list (APPEND HDF5_CMAKE_Fortran_FLAGS "-ffree-form" "-fimplicit-none")
     if (CMAKE_Fortran_COMPILER_VERSION VERSION_LESS 8.0 AND NOT CMAKE_Fortran_COMPILER_VERSION VERSION_LESS 4.6)
       list (APPEND HDF5_CMAKE_Fortran_FLAGS "-std=f2008ts")
@@ -92,7 +93,7 @@ if (NOT MSVC AND NOT MINGW)
     # Append more extra warning flags that only gcc 5.x+ knows about
     if (NOT CMAKE_Fortran_COMPILER_VERSION VERSION_LESS 5.0)
       if (HDF5_ENABLE_DEV_WARNINGS)
-        ADD_H5_FLAGS (HDF5_CMAKE_Fortran_FLAGS "${HDF5_SOURCE_DIR}/config/gnu-warnings/developer-gfort-5")
+        ADD_H5_FLAGS (HDF5_CMAKE_Fortran_FLAGS "${HDF5_SOURCE_DIR}/config/gnu-warnings/gfort-developer-5")
       endif ()
     endif ()
 
diff --git a/config/gnu-fflags b/config/gnu-fflags
index 1333ce5..0230e5c 100644
--- a/config/gnu-fflags
+++ b/config/gnu-fflags
@@ -150,6 +150,9 @@ if test "X-gfortran" = "X-$f9x_vendor"; then
 
     H5_FCFLAGS="$H5_FCFLAGS $(load_gnu_arguments gfort-general)"
 
+    NO_DEVELOPER_WARNING_FCFLAGS="$NO_DEVELOPER_WARNING_FCFLAGS $(load_gnu_arguments gfort-no-developer-general)"
+    DEVELOPER_WARNING_FCFLAGS="$DEVELOPER_WARNING_FCFLAGS $(load_gnu_arguments gfort-developer-general)"
+
     #############################
     # Version-specific warnings #
     #############################
@@ -163,7 +166,7 @@ if test "X-gfortran" = "X-$f9x_vendor"; then
 
     # gfortran >= 5
     if test $f9x_vers_major -ge 5; then
-        DEVELOPER_WARNING_FCFLAGS="$DEVELOPER_WARNING_FCFLAGS $(load_gnu_arguments developer-gfort-5)"
+        DEVELOPER_WARNING_FCFLAGS="$DEVELOPER_WARNING_FCFLAGS $(load_gnu_arguments gfort-developer-5)"
     fi
 
     # gfortran >= 6
diff --git a/config/gnu-warnings/developer-gfort-5 b/config/gnu-warnings/gfort-developer-5
index c5d3850..c5d3850 100644
--- a/config/gnu-warnings/developer-gfort-5
+++ b/config/gnu-warnings/gfort-developer-5
diff --git a/config/gnu-warnings/gfort-developer-general b/config/gnu-warnings/gfort-developer-general
new file mode 100644
index 0000000..dde15fe
--- /dev/null
+++ b/config/gnu-warnings/gfort-developer-general
@@ -0,0 +1,3 @@
+# There is no easy way in Fortran to indicate parameters are intentionally
+# unused and many callbacks will have these, generating a lot of noise.
+-Wunused-dummy-argument
diff --git a/config/gnu-warnings/gfort-no-developer-general b/config/gnu-warnings/gfort-no-developer-general
new file mode 100644
index 0000000..bfcba22
--- /dev/null
+++ b/config/gnu-warnings/gfort-no-developer-general
@@ -0,0 +1,3 @@
+# There is no easy way in Fortran to indicate parameters are intentionally
+# unused and many callbacks will have these, generating a lot of noise.
+-Wno-unused-dummy-argument