[svn-r26412] Merge of r26081-2, 26226, and 26399 from the autotools rework branch.

Various tweaks for autotools thread-safety and Pthreads support.

- Moved the check for pthread_attr_setscope() into the thread-safe
  checks section. Documented its necessity and added a cross-compiling
  option and helpful comment.

- Moved the high-level library checks up to the same place where
  Fortran and C++ are checked. This will make it easier to handle
  threadsafe/high-level combinations later.

- Also changed the default of --enable-pthread to 'check', which is
  the same as the old 'yes' behavior where we just check the standard
  locations. 'yes' and 'no' are still accepted, though 'no' will
  currently produce an error since the autotools only support Pthreads.

Fixes: HDFFV-9087

Tested on: h5committest
           jam (w/ threadsafe)

1 files changed, 58 insertions, 41 deletions

diff --git a/configure.ac b/configure.ac
index c5e456f..b8f1531 100644
--- a/configure.ac
+++ b/configure.ac
@@ -538,7 +538,7 @@ AC_SUBST(HL_FOR) HL_FOR=""
 AC_MSG_CHECKING([if high level library is enabled])
 AC_ARG_ENABLE([hl],
      [AS_HELP_STRING([--enable-hl],
-                     [Enable the high-level library [default=yes]])],
+                     [Enable the high level library [default=yes]])],
      [HDF5_HL=$enableval],
      [HDF5_HL=yes])
 
@@ -1596,9 +1596,15 @@ AC_CACHE_SAVE
 AC_MSG_CHECKING([for thread safe support])
 AC_ARG_ENABLE([threadsafe],
               [AS_HELP_STRING([--enable-threadsafe],
-                              [Enable thread-safe capability])],
+                              [Enable thread-safe capability. This will disable the high-level library.
+                              You can override this behavior by specifying --enable-hl and --enable-unsupported.
+                              [default=no]])],
               [THREADSAFE=$enableval])
 
+## NOTE: The high-level, C++, and Fortran interfaces are not compatible
+## with the thread-safety option because the lock is not hoisted
+## into the higher-level API calls.
+
 ## The --enable-threadsafe flag is not compatible with --enable-cxx.
 ## If the user tried to specify both flags, throw an error, unless
 ## they also provided the --enable-unsupported flag.
@@ -1608,7 +1614,7 @@ if test "X${ALLOW_UNSUPPORTED}" != "Xyes"; then
   fi
 fi
 
-## --enable-threadsafe is also incompatible with --enable-fortran, unless
+## --enable-threadsafe is also incompatible with --enable-fortran unless
 ## --enable-unsupported has been specified on the configure line.
 if test "X${ALLOW_UNSUPPORTED}" != "Xyes"; then
   if test "X${HDF_FORTRAN}" = "Xyes" -a "X${enable_threadsafe}" = "Xyes"; then
@@ -1616,6 +1622,7 @@ if test "X${ALLOW_UNSUPPORTED}" != "Xyes"; then
   fi
 fi
 
+
 case "X-$THREADSAFE" in
   X-|X-no)
     AC_MSG_RESULT([no])
@@ -1634,32 +1641,31 @@ if test "X$THREADSAFE" = "Xyes"; then
     AC_DEFINE([HAVE_THREADSAFE], [1], [Define if we have thread safe support])
 
     ## ----------------------------------------------------------------------
-    ## Is the pthreads library present?  It has a header file `pthread.h' and
+    ## Is the Pthreads library present?  It has a header file `pthread.h' and
     ## a library `-lpthread' and their locations might be specified with the
     ## `--with-pthread' command-line switch.  The value is an include path
     ## and/or a library path.  If the library path is specified then it must
     ## be preceded by a comma.
     ##
     ## Thread-safety in HDF5 only uses Pthreads via configure, so the
-    ## default is "yes", though this only has an effect when
+    ## default is "check", though this only has an effect when
     ## --enable-threadsafe is specified.
     AC_SUBST([HAVE_PTHREAD]) HAVE_PTHREAD=yes
     AC_ARG_WITH([pthread],
                 [AS_HELP_STRING([--with-pthread=DIR],
-                                [Specify alternative path to Pthreads library when thread-safe capability is built])],,
-                [withval=yes])
+                                [Specify alternative path to Pthreads library when
+                                thread-safe capability is built.])],,
+                [withval=check])
 
     case "$withval" in
-      yes)
+      check | yes)
         AC_CHECK_HEADERS([pthread.h],, [unset HAVE_PTHREAD])
         if test "x$HAVE_PTHREAD" = "xyes"; then
           AC_CHECK_LIB([pthread], [pthread_self],, [unset HAVE_PTHREAD])
         fi
         ;;
       no)
-        AC_MSG_CHECKING([for pthread])
-        AC_MSG_RESULT([suppressed])
-        unset HAVE_PTHREAD
+        AC_MSG_ERROR([Must use Pthreads with thread safety])
         ;;
       *)
         case "$withval" in
@@ -1708,6 +1714,47 @@ if test "X$THREADSAFE" = "Xyes"; then
         fi
         ;;
     esac
+
+    ## ----------------------------------------------------------------------
+    ## Check if pthread_attr_setscope(&attribute, PTHREAD_SCOPE_SYSTEM)
+    ## is supported on this system
+    ##
+    ## Unfortunately, this probably needs to be an AC_RUN_IFELSE since
+    ## it's impossible to determine if PTHREAD_SCOPE_SYSTEM is
+    ## supported a priori. POSIX.1-2001 requires that a conformant
+    ## system need only support one of SYSTEM or PROCESS scopes.
+    ##
+    ## For cross-compiling, we've added a pessimistic 'no'. You can
+    ## hand-hack the config file if you know otherwise.
+    AC_MSG_CHECKING([Pthreads supports system scope])
+    AC_CACHE_VAL([hdf5_cv_system_scope_threads],
+      [AC_RUN_IFELSE(
+        [AC_LANG_PROGRAM([
+            #if STDC_HEADERS
+            #include <stdlib.h>
+            #include <pthread.h>
+            #endif
+        ],[
+            int main(void)
+            {
+              pthread_attr_t attribute;
+              int ret;
+
+              pthread_attr_init(&attribute);
+              ret=pthread_attr_setscope(&attribute, PTHREAD_SCOPE_SYSTEM);
+              exit(ret==0 ? 0 : 1);
+            }
+        ])]
+      , [hdf5_cv_system_scope_threads=yes], [hdf5_cv_system_scope_threads=no], [hdf5_cv_system_scope_threads=no])])
+
+    if test ${hdf5_cv_system_scope_threads} = "yes"; then
+      AC_DEFINE([SYSTEM_SCOPE_THREADS], [1],
+                [Define if your system supports pthread_attr_setscope(&attribute, PTHREAD_SCOPE_SYSTEM) call.])
+      AC_MSG_RESULT([yes])
+    else
+      AC_MSG_RESULT([no])
+      AC_MSG_NOTICE([Always 'no' if cross-compiling. Edit the config file if your platform supports pthread_attr_setscope(&attribute, PTHREAD_SCOPE_SYSTEM).])
+    fi
 fi
 
 ## ----------------------------------------------------------------------
@@ -1962,36 +2009,6 @@ AC_MSG_RESULT([%${hdf5_cv_printf_ll}d and %${hdf5_cv_printf_ll}u])
 AC_DEFINE_UNQUOTED([PRINTF_LL_WIDTH], ["$hdf5_cv_printf_ll"], 
                    [Width for printf() for type `long long' or `__int64', use `ll'])
 
-## ----------------------------------------------------------------------
-## Check if pthread_attr_setscope(&attribute, PTHREAD_SCOPE_SYSTEM)
-## is supported on this system
-##
-AC_MSG_CHECKING([Threads support system scope])
-AC_CACHE_VAL([hdf5_cv_system_scope_threads],
-  [AC_TRY_RUN([
-    #if STDC_HEADERS
-    #include <stdlib.h>
-    #include <pthread.h>
-    #endif
-
-    int main(void)
-    {
-      pthread_attr_t attribute;
-      int ret;
-
-      pthread_attr_init(&attribute);
-      ret=pthread_attr_setscope(&attribute, PTHREAD_SCOPE_SYSTEM);
-      exit(ret==0 ? 0 : 1);
-    }
-  ], [hdf5_cv_system_scope_threads=yes], [hdf5_cv_system_scope_threads=no],)])
-
-if test ${hdf5_cv_system_scope_threads} = "yes"; then
-  AC_DEFINE([SYSTEM_SCOPE_THREADS], [1],
-            [Define if your system supports pthread_attr_setscope(&attribute, PTHREAD_SCOPE_SYSTEM) call.])
-  AC_MSG_RESULT([yes])
-else
-  AC_MSG_RESULT([no])
-fi
 
 ## ----------------------------------------------------------------------
 ## Turn on debugging by setting compiler flags