[svn-r26326] Merge of r26275 from the trunk

- Updated configure.ac so that the direct VFD can now be built
  without specifying _GNU_SOURCE, etc. on the command line.

- The direct VFD is now disabled by default. It was previously
  enabled, but the configuration script couldn't configure it
  properly, making it a moot point.

Fixes: HDFFV-9057, HDFFV-7567, HDFFV-9088, HDFFV-7566

Tested on jam (configure/make in various configurations only)

4 files changed, 113 insertions, 106 deletions

diff --git a/configure b/configure
index a6ba0f1..5ef3811 100755
--- a/configure
+++ b/configure
@@ -1,5 +1,5 @@
 #! /bin/sh
-# From configure.ac Id: configure.ac 26310 2015-02-26 14:42:05Z derobins .
+# From configure.ac Id: configure.ac 26314 2015-02-26 15:21:33Z brtnfld .
 # Guess values for system-dependent variables and create Makefiles.
 # Generated by GNU Autoconf 2.69 for HDF5 1.8.15-snap11.
 #
@@ -1616,8 +1616,9 @@ Optional Features:
   --enable-filters=all    Turn on all internal I/O filters. One may also
                           specify a comma-separated list of filters or the
                           word no. The default is all internal I/O filters.
-  --enable-direct-vfd     Build the Direct I/O Virtual File Driver
-                          [default=yes]
+  --enable-direct-vfd     Build the direct I/O virtual file driver (VFD). This
+                          is based on the POSIX (sec2) VFD and requires the
+                          open() call to take the O_DIRECT flag. [default=no]
   --enable-dconv-exception
                           if exception handling functions is checked during
                           data conversions [default=yes]
@@ -23104,19 +23105,28 @@ case "$host_cpu-$host_vendor-$host_os" in
     ## Add POSIX support on Linux systems, so <features.h> defines
     ## __USE_POSIX, which is required to get the prototype for fdopen
     ## defined correctly in <stdio.h>.
+    ##
     ## This flag was removed from h5cc as of 2009-10-17 when it was found
     ## that the flag broke compiling netCDF-4 code with h5cc, but kept in
     ## H5_CPPFLAGS because fdopen and HDfdopen fail without it. HDfdopen
     ## is used only by H5_debug_mask which is used only when debugging in
     ## H5_init_library (all in H5.c).  When the flag was removed this was
     ## the only compile failure noted.
+    ##
     ## This was originally defined as _POSIX_SOURCE which was updated to
     ## _POSIX_C_SOURCE=199506L to expose a greater amount of POSIX
     ## functionality so clock_gettime and CLOCK_MONOTONIC are defined
-    ## correctly.
+    ## correctly. This was later updated to 200112L so that
+    ## posix_memalign() is visible for the direct VFD code on Linux
+    ## systems.
+    ##
     ## POSIX feature information can be found in the gcc manual at:
     ## http://www.gnu.org/s/libc/manual/html_node/Feature-Test-Macros.html
-    H5_CPPFLAGS="-D_POSIX_C_SOURCE=199506L $H5_CPPFLAGS"
+    H5_CPPFLAGS="-D_POSIX_C_SOURCE=200112L $H5_CPPFLAGS"
+
+    ## Need to add this so that O_DIRECT is visible for the direct
+    ## VFD on Linux systems.
+    AM_CPPFLAGS="-D_GNU_SOURCE $AM_CPPFLAGS"
 
     ## Also add BSD support on Linux systems, so <features.h> defines
     ## __USE_BSD, which is required to get the prototype for strdup
@@ -28348,94 +28358,65 @@ fi
 ## Check if Direct I/O driver is enabled by --enable-direct-vfd
 ##
 
-{ $as_echo "$as_me:${as_lineno-$LINENO}: checking for Direct Virtual File Driver support" >&5
-$as_echo_n "checking for Direct Virtual File Driver support... " >&6; }
+## Check these regardless. If the checks are moved inside the main
+## direct VFD block, the output is nested.
 
-# Check whether --enable-direct-vfd was given.
-if test "${enable_direct_vfd+set}" = set; then :
-  enableval=$enable_direct_vfd; DIRECT_VFD=$enableval
-else
-  DIRECT_VFD=yes
-fi
-
-
-if test "$DIRECT_VFD" = "yes"; then
-   if ${hdf5_cv_direct_io+:} false; then :
+if ${hdf5_cv_direct_io+:} false; then :
   $as_echo_n "(cached) " >&6
 else
-  if test "$cross_compiling" = yes; then :
-  { { $as_echo "$as_me:${as_lineno-$LINENO}: error: in \`$ac_pwd':" >&5
-$as_echo "$as_me: error: in \`$ac_pwd':" >&2;}
-as_fn_error $? "cannot run test program while cross compiling
-See \`config.log' for more details" "$LINENO" 5; }
-else
-  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
-/* end confdefs.h.  */
-
-	  #include <sys/types.h>
-	  #include <sys/stat.h>
-	  #include <fcntl.h>
-          int main(void)
-          {
-             int fid;
-             if((fid=open("tst_file", O_CREAT | O_TRUNC | O_DIRECT, 0755))<0)
-		exit(1);
-             close(fid);
-             remove("tst_file");
-             exit (0);
-          }
-_ACEOF
-if ac_fn_c_try_run "$LINENO"; then :
-  cat confdefs.h - <<_ACEOF >conftest.$ac_ext
-/* end confdefs.h.  */
-
-#ifdef FC_DUMMY_MAIN
-#ifndef FC_DUMMY_MAIN_EQ_F77
-#  ifdef __cplusplus
-     extern "C"
-#  endif
-   int FC_DUMMY_MAIN() { return 1; }
-#endif
-#endif
-int
-main ()
-{
-posix_memalign()
-  ;
-  return 0;
-}
-_ACEOF
-if ac_fn_c_try_link "$LINENO"; then :
+  ac_fn_c_check_decl "$LINENO" "O_DIRECT" "ac_cv_have_decl_O_DIRECT" "#include <fcntl.h>
+"
+if test "x$ac_cv_have_decl_O_DIRECT" = xyes; then :
   hdf5_cv_direct_io=yes
 else
   hdf5_cv_direct_io=no
 fi
-rm -f core conftest.err conftest.$ac_objext \
-    conftest$ac_exeext conftest.$ac_ext
+
+fi
+
+if ${hdf5_cv_posix_memalign+:} false; then :
+  $as_echo_n "(cached) " >&6
 else
-  hdf5_cv_direct_io=no
+  ac_fn_c_check_func "$LINENO" "posix_memalign" "ac_cv_func_posix_memalign"
+if test "x$ac_cv_func_posix_memalign" = xyes; then :
+  hdf5_cv_posix_memalign=yes
+else
+  hdf5_cv_posix_memalign=no
 fi
-rm -f core *.core core.conftest.* gmon.out bb.out conftest$ac_exeext \
-  conftest.$ac_objext conftest.beam conftest.$ac_ext
+
 fi
 
+
+{ $as_echo "$as_me:${as_lineno-$LINENO}: checking if the direct I/O virtual file driver (VFD) is enabled" >&5
+$as_echo_n "checking if the direct I/O virtual file driver (VFD) is enabled... " >&6; }
+
+# Check whether --enable-direct-vfd was given.
+if test "${enable_direct_vfd+set}" = set; then :
+  enableval=$enable_direct_vfd; DIRECT_VFD=$enableval
+else
+  DIRECT_VFD=no
 fi
 
 
-   if test ${hdf5_cv_direct_io} = "yes"; then
-      { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
+if test "X$DIRECT_VFD" = "Xyes"; then
+    if test ${hdf5_cv_direct_io} = "yes" && test ${hdf5_cv_posix_memalign} = "yes" ; then
+        { $as_echo "$as_me:${as_lineno-$LINENO}: result: yes" >&5
 $as_echo "yes" >&6; }
 
 $as_echo "#define HAVE_DIRECT 1" >>confdefs.h
 
-   else
-      { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+    else
+        { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
 $as_echo "no" >&6; }
-      DIRECT_VFD=no
-   fi
+        DIRECT_VFD=no
+        as_fn_error $? "The direct VFD was requested but cannot be built. This is either
+                     due to O_DIRECT not being found in fcntl.h or a lack of
+                     posix_memalign() on your system. Please re-configure without
+                     specifying --enable-direct-vfd." "$LINENO" 5
+    fi
 else
-      { $as_echo "$as_me:${as_lineno-$LINENO}: result: suppressed" >&5
-$as_echo "suppressed" >&6; }
+    { $as_echo "$as_me:${as_lineno-$LINENO}: result: no" >&5
+$as_echo "no" >&6; }
 fi
 
  if test "X$DIRECT_VFD" = "Xyes"; then
diff --git a/configure.ac b/configure.ac
index 4c7eeb7..5e5b59f 100644
--- a/configure.ac
+++ b/configure.ac
@@ -1115,19 +1115,28 @@ case "$host_cpu-$host_vendor-$host_os" in
     ## Add POSIX support on Linux systems, so <features.h> defines
     ## __USE_POSIX, which is required to get the prototype for fdopen
     ## defined correctly in <stdio.h>. 
+    ##
     ## This flag was removed from h5cc as of 2009-10-17 when it was found
     ## that the flag broke compiling netCDF-4 code with h5cc, but kept in 
     ## H5_CPPFLAGS because fdopen and HDfdopen fail without it. HDfdopen
     ## is used only by H5_debug_mask which is used only when debugging in
     ## H5_init_library (all in H5.c).  When the flag was removed this was
     ## the only compile failure noted.
+    ##
     ## This was originally defined as _POSIX_SOURCE which was updated to
     ## _POSIX_C_SOURCE=199506L to expose a greater amount of POSIX
     ## functionality so clock_gettime and CLOCK_MONOTONIC are defined
-    ## correctly.
+    ## correctly. This was later updated to 200112L so that
+    ## posix_memalign() is visible for the direct VFD code on Linux
+    ## systems.
+    ##
     ## POSIX feature information can be found in the gcc manual at:
     ## http://www.gnu.org/s/libc/manual/html_node/Feature-Test-Macros.html
-    H5_CPPFLAGS="-D_POSIX_C_SOURCE=199506L $H5_CPPFLAGS"
+    H5_CPPFLAGS="-D_POSIX_C_SOURCE=200112L $H5_CPPFLAGS"
+
+    ## Need to add this so that O_DIRECT is visible for the direct
+    ## VFD on Linux systems.
+    AM_CPPFLAGS="-D_GNU_SOURCE $AM_CPPFLAGS"
 
     ## Also add BSD support on Linux systems, so <features.h> defines
     ## __USE_BSD, which is required to get the prototype for strdup
@@ -2542,40 +2551,39 @@ fi
 ## Check if Direct I/O driver is enabled by --enable-direct-vfd
 ##
 
-AC_MSG_CHECKING([for Direct Virtual File Driver support])
+## Check these regardless. If the checks are moved inside the main
+## direct VFD block, the output is nested.
+
+AC_CACHE_VAL([hdf5_cv_direct_io],
+    AC_CHECK_DECL([O_DIRECT], [hdf5_cv_direct_io=yes], [hdf5_cv_direct_io=no], [[#include <fcntl.h>]]))
+AC_CACHE_VAL([hdf5_cv_posix_memalign],
+    AC_CHECK_FUNC([posix_memalign], [hdf5_cv_posix_memalign=yes], [hdf5_cv_posix_memalign=no]))
+
+AC_MSG_CHECKING([if the direct I/O virtual file driver (VFD) is enabled])
 
 AC_ARG_ENABLE([direct-vfd],
               [AS_HELP_STRING([--enable-direct-vfd],
-                              [Build the Direct I/O Virtual File Driver
-                               [default=yes]])],
-              [DIRECT_VFD=$enableval], [DIRECT_VFD=yes])
-
-if test "$DIRECT_VFD" = "yes"; then
-   AC_CACHE_VAL([hdf5_cv_direct_io],
-       [AC_TRY_RUN([
-	  #include <sys/types.h>
-	  #include <sys/stat.h>
-	  #include <fcntl.h>
-          int main(void)
-          {
-             int fid; 
-             if((fid=open("tst_file", O_CREAT | O_TRUNC | O_DIRECT, 0755))<0)
-		exit(1);
-             close(fid);  
-             remove("tst_file"); 
-             exit (0);
-          }], [AC_TRY_LINK(, [posix_memalign()], [hdf5_cv_direct_io=yes], [hdf5_cv_direct_io=no])], [hdf5_cv_direct_io=no],)])
-
-   if test ${hdf5_cv_direct_io} = "yes"; then
-      AC_MSG_RESULT([yes])
-      AC_DEFINE([HAVE_DIRECT], [1],
-                [Define if the direct I/O virtual file driver should be compiled])
-   else
-      AC_MSG_RESULT([no])
-      DIRECT_VFD=no
-   fi
+                              [Build the direct I/O virtual file driver (VFD).
+                               This is based on the POSIX (sec2) VFD and
+                               requires the open() call to take the O_DIRECT
+                               flag. [default=no]])],
+              [DIRECT_VFD=$enableval], [DIRECT_VFD=no])
+
+if test "X$DIRECT_VFD" = "Xyes"; then
+    if test ${hdf5_cv_direct_io} = "yes" && test ${hdf5_cv_posix_memalign} = "yes" ; then
+        AC_MSG_RESULT([yes])
+        AC_DEFINE([HAVE_DIRECT], [1],
+                [Define if the direct I/O virtual file driver (VFD) should be compiled])
+    else
+        AC_MSG_RESULT([no])
+        DIRECT_VFD=no
+        AC_MSG_ERROR([The direct VFD was requested but cannot be built. This is either
+                     due to O_DIRECT not being found in fcntl.h or a lack of
+                     posix_memalign() on your system. Please re-configure without
+                     specifying --enable-direct-vfd.])
+    fi
 else
-      AC_MSG_RESULT([suppressed])
+    AC_MSG_RESULT([no])
 fi
 
 AM_CONDITIONAL([DIRECT_VFD_CONDITIONAL], [test "X$DIRECT_VFD" = "Xyes"])
diff --git a/release_docs/RELEASE.txt b/release_docs/RELEASE.txt
index ed5ea63..0c600e0 100644
--- a/release_docs/RELEASE.txt
+++ b/release_docs/RELEASE.txt
@@ -114,6 +114,24 @@ New Features
 
       (DER - 2015-02-26, HDFFV-9081)
 
+    - Direct VFD configure behavior
+
+      The configure options for Linux now allow the direct VFD to built
+      without passing additional compiler options/defines like _GNU_SOURCE.
+      Passing --enable-direct-vfd is now all that is needed to enable
+      the feature.
+
+      The direct VFD is now disabled by default since it is intended for
+      specialized audiences. It was previously enabled by default, but the
+      configure script did not set correct POSIX levels, etc. making this
+      a moot point.
+
+      Note that the direct VFD can only be configured on Linux when
+      the O_DIRECT flag to open()/create() and posix_memalign() function
+      are available. This is unchanged from previous behavior.
+
+      (DER - 2015-02-26, HDFFV-9057, 7567, 9088, 7566)
+
     Library
     -------
     - None
diff --git a/src/H5config.h.in b/src/H5config.h.in
index 0c09fe6..6b6ffdd 100644
--- a/src/H5config.h.in
+++ b/src/H5config.h.in
@@ -87,7 +87,7 @@
 /* Define to 1 if you have the `difftime' function. */
 #undef HAVE_DIFFTIME
 
-/* Define if the direct I/O virtual file driver should be compiled */
+/* Define if the direct I/O virtual file driver (VFD) should be compiled */
 #undef HAVE_DIRECT
 
 /* Define to 1 if you have the <dirent.h> header file. */