BUG: GetMailSlotInfo Returns Incorrect lpNextSize Value

ID: Q192276

The information in this article applies to:

Microsoft Win32 Software Development Kit (SDK) on the following platforms:
```
    - Microsoft Windows 95
    - Microsoft Windows 98
```

SYMPTOMS

If you call the API GetMailSlotInfo under Windows 95 OEM Service Release 2 (OSR2) or Windows 98 without a Network Client installed, you receive an incorrect value (usually in the millions) or a negative number for the lpNextSize parameter. If you repeatedly call the function, it usually returns the correct value.

CAUSE

The problem occurs only when you do not have a Network Client installed. If any Network Client is installed, the API functions correctly.

RESOLUTION

Do one of the following to work around this problem:

Install the Dial-Up Network Adapter on any system experiencing the problem. You do not need to set up the adapter. Just installing it will correct the problem.
Put a loop around the GetMailSlotInfo call that continues to call it until lpNextSize returns a positive value that is within the limits of the mailslot information expected or zero. However, this workaround causes a great deal of unnecessary processing and might effect the performance of other programs.

STATUS

Microsoft has confirmed this to be a problem in the Microsoft products listed at the beginning of this article.

MORE INFORMATION

This problem only occurs under Windows 95 OEM Service Release 2 and later. GetMailSlotInfo works correctly on the original version of Windows 95 and Windows 95 with Service Pack 1 installed.

Step-by-Step Procedures

To install the Dialup Network Adapter:

1. Click Start, click Settings, and click Control Panel.

2. Double-click Add/Remove Programs. The Add/Remove Programs Properties

   dialog box appears.

3. Click the Windows Setup tab.

4. Under Components, select Communications.

5. Click Details... The Communications dialog box appears. Make sure

   Dial-Up Networking is selected.

6. Click OK to close the Communications dialog box, and then click OK to

   close the Add/Remove Programs Properties dialog box.

7. You might be asked to insert your Windows installation disks or CD.

   Follow the instructions as they appear on the screen. At the end of the
   installation, Windows will ask you to restart your computer. After you
   have restarted your computer, the call to GetMailSlotInfo should work
   correctly.

Additional query words:

Keywords          : kbnetwork kbIPC kbSDKPlatform kbWinOS95bug kbWinOS98bug kbMailslot kbGrpNet 
Issue type        : kbbug
Solution Type     : kbnofix

Last Reviewed: September 5, 1998