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C6276

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warning C6276: Cast between semantically different string types: char* to wchar_t*. Use of invalid string can lead to undefined behavior

This warning indicates a potentially incorrect cast from an ANSI string (char_t*) to a UNICODE string (wchar_t *). Because UNICODE strings have a character size of 2 bytes, this cast might yield strings that are not correctly terminated. Using such strings with the wcs* library of functions could cause buffer overruns and access violations.

Example

The following code generates this warning:

#include <windows.h>  
VOID f()  
{  
   WCHAR szBuffer[8];  
   LPWSTR pSrc;  
  
   pSrc = (LPWSTR)"a";  
   wcscpy(szBuffer, pSrc);   
}

The following code corrects this warning by appending the letter L to represent the ASCII character as a wide character:

#include <windows.h>  
  
VOID f()  
{  
   WCHAR szBuffer[8];  
   LPWSTR pSrc;  
  
   pSrc = L"a";  
   wcscpy(szBuffer, pSrc);  
}

The following code uses the safe string manipulation function, wcscpy_s, to correct this warning:

#include <windows.h>  
  
VOID f()  
{  
   WCHAR szBuffer[8];  
   LPWSTR pSrc;  
   pSrc = L"a";  
   wcscpy_s(szBuffer,8,pSrc);   
}