DdeCreateStringHandleA function (ddeml.h)

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 DdeCreateStringHandleA(
  [in] DWORD  idInst,
  [in] LPCSTR psz,
  [in] int    iCodePage
);

Parameters

[in] idInst

Type: DWORD

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

[in] psz

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.

[in] iCodePage

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:

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

See also

Conceptual

DdeAccessData

DdeCmpStringHandles

DdeFreeStringHandle

DdeInitialize

DdeKeepStringHandle

DdeQueryString

Dynamic Data Exchange Management Library

Reference