Issue identified, see #159 for specifics. Also see http://stackoverfl…

…ow.com/questions/10541200/is-the-behaviour-of-casting-a-negative-double-to-unsigned-int-defined-in-the-c-s for some background info that lead me to the fix.

gdb.txt

@@ -1,4 +1,8 @@
-break cdf5_gh159_test.c:127
+break cdf5_gh159_test.c:52
+commands
+continue
+end
+break cdf5_gh159_test.c:145
 commands
 break ncx_putn_uchar_double
 break ncx.c:4845

nc_test/cdf5_gh159_test.c

@@ -30,10 +30,28 @@ main() {/* create cdf5_test */
  /* variable ids */
  int y3_id;
  int y3d_id;
-
+ int i = 0;
  int y3_dims[RANK_y3];
  int y3d_dims[RANK_y3d];
 
+ /* Lets do a bit of other
+ testing here too. */
+ {
+ int xx = 0;
+ double *tp = (double*)malloc(sizeof(double)*3);
+ double *tph = tp;
+ unsigned char *xp = (unsigned char *)malloc(sizeof(unsigned char)*3);
+ unsigned char *xph = xp;
+ tp[0] = -2;
+ tp[1] = 255;
+ tp[2] = -1;
+
+ for(i = 0; i < 3; i++)
+ *xp++ = (unsigned)(signed char)*tp++;
+
+ xx = 1;
+ }
+
  /* enter define mode */
  stat = nc_create(FILENAME, NC_CLOBBER | NC_64BIT_DATA, &ncid);
  check_err(stat,__LINE__,__FILE__);