[svn-r9826] Purpose: Bug fix

Description:  Intel compiler on Linux has some problem to convert long double to
unsigned int correctly.

Solution:  Detect the problem in configure and define a macro to skip this test
if it happens.

Platforms tested: eirene and fuss.  Simple change.

1 files changed, 31 insertions, 0 deletions

diff --git a/configure.in b/configure.in
index b9c3846..7790aab 100644
--- a/configure.in
+++ b/configure.in
@@ -2734,6 +2734,37 @@ else
   AC_MSG_RESULT([no])
 fi
 
+dnl ----------------------------------------------------------------------
+dnl Set the flag to indicate that the machine can accurately convert
+dnl 'long double' to 'unsigned int' values.  (This flag should be set for 
+dnl all machines, except for some Intel compilers on some Linux.)
+dnl
+AC_MSG_CHECKING([if converting long double to unsigned int values works])
+
+AC_CACHE_VAL([hdf5_cv_ldouble_to_uint_works],
+    [AC_TRY_RUN([
+    int main(void)
+    {
+        long double ld = 2733248032.9183987530L;
+        unsigned int i;
+        int           ret = 0;
+
+        i = (unsigned int)ld;
+        if(i!=2733248032 && i!=2733248031 && i!=2733248033)
+            ret = 1;
+
+done:
+        exit(ret);
+    }
+    ], [hdf5_cv_ldouble_to_uint_works=yes], [hdf5_cv_ldouble_to_uint_works=no],)])
+
+if test ${hdf5_cv_ldouble_to_uint_works} = "yes"; then
+  AC_DEFINE([CV_LDOUBLE_TO_UINT_WORKS], [1],
+            [Define if your system can convert long double to unsigned int values correctly.])
+  AC_MSG_RESULT([yes])
+else
+  AC_MSG_RESULT([no])
+fi
 
 dnl ----------------------------------------------------------------------
 dnl Set the flag to indicate that the machine can _compile_