Microsoft KB Archive/102570

From BetaArchive Wiki
< Microsoft KB Archive
Revision as of 08:24, 20 July 2020 by X010 (talk | contribs) (Text replacement - """ to """)
(diff) ← Older revision | Latest revision (diff) | Newer revision → (diff)

INFO: DdeCreateStringHandle() lpszString param

Q102570



The information in this article applies to:


  • Microsoft Windows Software Development Kit (SDK) 3.1
  • Microsoft Win32 Application Programming Interface (API), used with:
    • Microsoft Windows NT Server versions 3.5, 3.51
    • Microsoft Windows NT Workstation versions 3.5, 3.51
    • Microsoft Windows 95





SUMMARY

The documentation for the DdeCreateStringHandle() function in the Windows 3.1 Software Development Kit (SDK) "Programmer's Reference, Volume 2: Functions" incorrectly states that the lpszString parameter may point to a buffer of a null-terminated string of any length, when the string is actually limited to 255 characters.

DDEML string-management functions are internally implemented using global atom functions. DdeCreateStringHandle() in particular, internally calls GlobalAddAtom(), and therefore inherits the same limitation as atoms to a maximum of 255 characters in length.



MORE INFORMATION

DDEML applications use string handles extensively to carry out DDE tasks. To obtain a string handle for a string, an application calls DdeCreateStringHandle(). This function registers the string with the system by adding the string to the global atom table, and returns a unique value identifying the string.

The global atom table table in Windows can maintain strings that are less than or equal to 255 characters in length. Any attempt to add a string of greater length to this global atom table will fail. Hence, a call to DdeCreateStringHandle() fails for strings over 255 characters long.

This limitation is by design. DDEML applications that use the DdeCreateStringHandle() function should conform to the 255-character limit. This limitation has been preserved on the Windows NT version of DDEML for compatibility reasons.

Additional query words: 3.10 3.50 4.00

Keywords : kbDDE
Issue type : kbinfo
Technology : kbAudDeveloper kbSDKSearch kbWin32sSearch kbWin32API kbWinSDKSearch


Last Reviewed: December 16, 2000
© 2001 Microsoft Corporation. All rights reserved. Terms of Use.