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DdeCreateStringHandle function

Creates a handle that identifies the specified string. A Dynamic Data Exchange (DDE) client or server application can pass the string handle as a parameter to other Dynamic Data Exchange Management Library (DDEML) functions.

Syntax


HSZ WINAPI DdeCreateStringHandle(
  _In_  DWORD idInst,
  _In_  LPTSTR psz,
  _In_  int iCodePage
);

Parameters

idInst [in]

Type: DWORD

The application instance identifier obtained by a previous call to the DdeInitialize function.

psz [in]

Type: LPTSTR

The null-terminated string for which a handle is to be created. This string can be up to 255 characters. The reason for this limit is that DDEML string management functions are implemented using atoms.

iCodePage [in]

Type: int

The code page to be used to render the string. This value should be either CP_WINANSI (the default code page) or CP_WINUNICODE, depending on whether the ANSI or Unicode version of DdeInitialize was called by the client application.

Return value

Type: HSZ

If the function succeeds, the return value is a string handle.

If the function fails, the return value is 0L.

The DdeGetLastError function can be used to get the error code, which can be one of the following values:

DMLERR_INVALIDPARAMETER
DMLERR_NO_ERROR
DMLERR_SYS_ERROR

Remarks

The value of a string handle is not related to the case of the string it identifies.

When an application either creates a string handle or receives one in the callback function and then uses the DdeKeepStringHandle function to keep it, the application must free that string handle when it is no longer needed.

An instance-specific string handle cannot be mapped from string handle to string and back to string handle. This is shown in the following example, in which the DdeQueryString function creates a string from a string handle and DdeCreateStringHandle creates a string handle from that string, but the two handles are not the same:


DWORD idInst; 
DWORD cb; 
HSZ hszInst, hszNew; 
PSZ pszInst; 
 
DdeQueryString(idInst, hszInst, pszInst, cb, CP_WINANSI); 
hszNew = DdeCreateStringHandle(idInst, pszInst, CP_WINANSI); 
// hszNew != hszInst ! 

Requirements

Minimum supported client

Windows 2000 Professional [desktop apps only]

Minimum supported server

Windows 2000 Server [desktop apps only]

Header

Ddeml.h (include Windows.h)

Library

User32.lib

DLL

User32.dll

Unicode and ANSI names

DdeCreateStringHandleW (Unicode) and DdeCreateStringHandleA (ANSI)

See also

Reference
DdeAccessData
DdeCmpStringHandles
DdeFreeStringHandle
DdeInitialize
DdeKeepStringHandle
DdeQueryString
Conceptual
Dynamic Data Exchange Management Library

 

 

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