BUG: Double Data Type Does Not Display Small Values Correctly

• Microsoft Visual FoxPro for Windows, versions 3.0, 3.0b, 5.0, 5.0a

SYMPTOMS

When the stored value is smaller than 10 to the minus (-)15th power, the new data type, known as double, is not displayed correctly in a table field.

Visual FoxPro should display numbers smaller than 10 to the -15th power. For example, the number 0.00000000000000009 (9 x 10 to the -17th power) should be displayed as 9.0000000000000E-17. You see this as .0000000000000000000 in a browse.

In Visual FoxPro versions 3.0 and 3.0b, values smaller than 10 to the -15th power are displayed as a string of zeros.

In Visual FoxPro 5.0, values between 10 to the -15th power and 10 to the -30th power are displayed as zeros. Values smaller than 10 to the -30th power are displayed correctly. For example, 9 x 10 to the -32nd power is displayed correctly as 9.0000000000000E-32.

Values between 10 to the -13th power and 10 to the -15th power may also appear incorrectly.

STATUS

Microsoft has confirmed this to be a problem in the Microsoft products listed at the beginning of this article. We are researching this problem and will post new information here in the Microsoft Knowledge Base as it becomes available.

MORE INFORMATION

The values are stored correctly, but displayed incorrectly. Arithmetic operations that use the values are performed correctly. To see the values, you must multiply them by a positive power of 10. As a result, the significant digits are within the range of values that are displayed correctly.

Steps to Reproduce Behavior

Visual FoxPro 3.0, 3.0b, and 5.0 may display the following commands in the Command window:

   CREATE TABLE dpt (dp B(18))     && Double data, 18 to right of decimal
   INSERT INTO dpt (dp) VALUES (9)
   BROWSE     && The data appears as a 9, a decimal, and 18 zeros
   REPLACE dp WITH dp/10**15  && 0. then 14 zeros followed by 9000
   REPLACE dp WITH dp/10      && 0. then 14 zeros followed by 1000
   REPLACE dp WITH 9          && Reset
   REPLACE dp WITH dp/10**31  && Correct in version 5, wrong in version 3.x
   REPLACE dp WITH dp/10**277 && Correct in version 5, zeros in version 3.x
   REPLACE dp WITH dp*10**308 && Restores 9.00000000000000000