Q191089: PRB: Multimedia API Calls May Fail with Long File Names

Article: Q191089
Product(s): Microsoft Visual Basic for Windows
Version(s): 
Operating System(s): 
Keyword(s): kbGrpDSVB
Last Modified: 11-JAN-2001

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The information in this article applies to:

- Microsoft Visual Basic Learning Edition for Windows, versions 5.0, 6.0 
- Microsoft Visual Basic Professional Edition for Windows, versions 5.0, 6.0 
- Microsoft Visual Basic Enterprise Edition for Windows, versions 5.0, 6.0 
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SYMPTOMS
========

Multimedia API calls such as "mciSendString" may fail when you pass a file path
or file name that uses long file names.

RESOLUTION
==========

Make sure you use a standard 8.3 path and file name. Or, wrap the path and file
name in quotes.

STATUS
======

This behavior is by design.

MORE INFORMATION
================

When using multimedia API calls to play multimedia files, the API call may fail
if the path or file name in the command string has embedded spaces. The
following example uses the mciSendString API to demonstrate this.

Steps to Reproduce Behavior
---------------------------

1. Create a new Standard EXE project. Form1 is created by default.

2. Using the Projects menu click Components to bring up the Components dialog
  box. On the Controls tab select "Microsoft Common Dialog Control" and click
  OK.

3. Place a CommonDialog control and two CommandButtons onto Form1.

4. Add the following code to Form1's module:

        Private Declare Function mciSendString Lib "winmm.dll" Alias _
         "mciSendStringA" (ByVal lpstrCommand As String, ByVal _
         lpstrReturnString As Any, ByVal uReturnLength As Long, ByVal _
         hwndCallback As Long) As Long

        Private Sub Command1_Click()
          CommonDialog1.ShowOpen
          Debug.Print CommonDialog1.filename
          Debug.Print mciSendString( _
            "open " & CommonDialog1.filename & " alias testfile", 0&, 0, 0)
          ' To work around the long file name limitation use the next line
          ' instead of the previous line, which adds quotes around the path
          ' and file name.
          'Debug.Print mciSendString( _
            "open " & """" & CommonDialog1.filename & """" _
           & " alias testfile", 0&, 0, 0)

          Debug.Print mciSendString("play testfile wait", 0&, 0, 0)
        End Sub

        Private Sub Command2_Click()
          Debug.Print mciSendString("close testfile", 0&, 0, 0)
        End Sub

        Private Sub Form_Load()
          Command1.Caption = "Open and Run"
          Command2.Caption = "Close MDI file"
        End Sub

5. Save and run the project.

6. Click on the Open button and select an .avi file that has a long file or path
  name. The mciSendString call will return an error. You will see this because
  the return value will be a non-zero.

7. Follow the comments in Command1_Click, then repeat step 6. The function
  should now succeed and return a zero.

Additional query words: kbVBp kbdsd kbDSupport kbVBp400 kbVBp500 kbVBp600 kbAPI kbmm kbds

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Keywords          : kbGrpDSVB 
Technology        : kbVBSearch kbAudDeveloper kbZNotKeyword6 kbZNotKeyword2 kbVB500Search kbVB600Search kbVBA500 kbVBA600 kbVB500 kbVB600
Issue type        : kbprb

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