Fixed the floating point number tests on Windows.

mysql-test/r/insert.result:
  Fixed the test cases.
mysql-test/t/cast.test:
  We need to do replace_result because warnings are printed by another procedure.
mysql-test/t/insert.test:
  Windows implements a different rounding rules in printf("%g"), thus we still need to do replace_result.
sql/field.cc:
  Limit the precision to avoid garbage past the significant digits.

mysql-test/r/insert.result

@@ -500,23 +500,23 @@ Warnings:
 Warning	1265	Data truncated for column 'c' at row 1
 SELECT * FROM t1;
 a	b	c
-9.999999000000000748	10	10
+9.999999	10	10
 1.225e-05	1.2e-05	1e-0
 0.0001225	0.00012	NULL
-0.122499999999999998	0.1225	NULL
-0.122587699999999994	0.12259	NULL
+0.1225	0.1225	NULL
+0.1225877	0.12259	NULL
 12.25	12.25	NULL
 12.25	12.25	12.2
 122500	122500	NULL
 12250000000	1.2e+10	NULL
-1225000000000000	1.2e+15	NULL
+1.225e+15	1.2e+15	NULL
 5000000	5000000	NULL
 1.25e+78	1.2e+78	NULL
 1.25e-94	1.2e-94	NULL
 1.25e+203	1e+203	NULL
 1.25e-175	1e-175	NULL
-1.225000000000000089	NULL	1.23
-1.370000000000000107	NULL	1.37
+1.225	NULL	1.23
+1.37	NULL	1.37
 -1.37	NULL	-1.3
 0.00187	NULL	0.00
 -0.0187	NULL	-0.0
@@ -554,23 +554,23 @@ INSERT INTO t1(a,c) VALUES (5000e+0, 5000e+0);
 INSERT INTO t1(a,c) VALUES (-5000e+0, -5000e+0);
 SELECT * FROM t1;
 a	b	c
-9.999999000000000748	10	9.999
+9.999999	10	9.999
 1.225e-05	1.2e-05	1e-05
 0.0001225	0.00012	NULL
-0.122499999999999998	0.1225	NULL
-0.122587699999999994	0.12259	NULL
+0.1225	0.1225	NULL
+0.1225877	0.12259	NULL
 12.25	12.25	NULL
 12.25	12.25	12.25
 122500	122500	NULL
 12250000000	1.2e+10	NULL
-1225000000000000	1.2e+15	NULL
+1.225e+15	1.2e+15	NULL
 5000000	5000000	NULL
 1.25e+78	1.2e+78	NULL
 1.25e-94	1.2e-94	NULL
 1.25e+203	1e+203	NULL
 1.25e-175	1e-175	NULL
-1.225000000000000089	NULL	1.225
-1.370000000000000107	NULL	1.37
+1.225	NULL	1.225
+1.37	NULL	1.37
 -1.37	NULL	-1.37
 0.00187	NULL	0.002
 -0.0187	NULL	-0.01

mysql-test/t/cast.test

@@ -177,6 +177,8 @@ select cast(1.0e+300 as signed int);
 CREATE TABLE t1 (f1 double);
 INSERT INTO t1 SET f1 = -1.0e+30 ;
 INSERT INTO t1 SET f1 = +1.0e+30 ;
+# Expected result is +-1e+30, but Windows returns +-1e+030.
+--replace_result 1e+030 1e+30
 SELECT f1 AS double_val, CAST(f1 AS SIGNED INT) AS cast_val FROM t1;
 DROP TABLE t1;					   
 

mysql-test/t/insert.test

@@ -386,7 +386,9 @@ INSERT INTO t1(a,c) VALUES (1.87e-3, 1.87e-3);
 INSERT INTO t1(a,c) VALUES (-1.87e-2, -1.87e-2);
 INSERT INTO t1(a,c) VALUES (5000e+0, 5000e+0);
 INSERT INTO t1(a,c) VALUES (-5000e+0, -5000e+0);
-
+# Expected results are "12.2" and "1.2e+78", but Windows returns "12.3" and
+# "1.3e+78" due to different rounding rules
+--replace_result 12.3 12.2 1.3e+78 1.2e+78
 SELECT * FROM t1;
 
 DROP TABLE t1;

sql/field.cc

@@ -5954,7 +5954,7 @@ int Field_str::store(double nr)
   if (exp >= (int) digits || exp < -4)
     digits= max(0, (int) (max_length - 5 - (exp >= 100 || exp <= -100)));
   
-  length= (uint) my_sprintf(buff, (buff, "%-.*g", digits, nr));
+  length= (uint) my_sprintf(buff, (buff, "%-.*g", min(digits, DBL_DIG ), nr));
 
 #ifdef __WIN__
   /*