Windows Safe String Function

HRESULT StringCbCopy(LPTSTR pszDest, size_t cbDest, LPCTSTR pszSrc);

HRESULT StringCbCopyA(LPSTR pszDest, size_t cbDest, LPCSTR pszSrc);

HRESULT StringCbCopyW(LPWSTR pszDest, size_t cbDest, LPCWSTR pszSrc);

HRESULT StringCbCopyEx(LPTSTR pszDest, size_t cbDest, LPCTSTR pszSrc, LPTSTR *ppszDestEnd, size_t *pcbRemaining, DWORD dwFlags);

HRESULT StringCbCopyExA(LPSTR pszDest, size_t cbDest, LPCSTR pszSrc, LPSTR *ppszDestEnd, size_t *pcbRemaining, DWORD dwFlags);

HRESULT StringCbCopyExW(LPWSTR pszDest, size_t cbDest, LPCWSTR pszSrc, LPWSTR *ppszDestEnd, size_t *pcbRemaining, DWORD dwFlags);

Internationalization (I18n) Function Overview

The StringCbCopy function is a replacement for locale-sensitive string copy functions. It copies pszStr to pszDest, using the byte size of the buffer stored in cbDest to ensure that the destination string buffer is not overrun. In the event of an error, a negative HRESULT value is returned, indicating the error.

StringCbCopyEx adds advanced functionality: It returns a pointer to the end of the destination string as well as the number of bytes left unused in that string, and uses dwFlags for additional control.

The narrow versions of these functions, StringCbCopyA and StringCbCopyExA, pass in single-byte or multibyte strings and lengths that refer to the number of bytes.

The wide versions of these functions, StringCbCopyW and StringCbCopyExW, pass in wide-character strings, but, like the narrow versions, lengths that refer to the number of bytes.

I18n Issues

Use the appropriate version of the function as required for internationalization support, and ensure that cbDest is set to the byte size of the destination string buffer. See Locale-Sensitive Length Functions for a discussion on multibyte and wide character sizes.

Recommended Replacements*

When possible, use the Generic version of the function, rather than the narrow or wide versions, and let the Windows #define UNICODE switch determine which version of the function will be called. These are shown as the first choices in the following table:

Microsoft Windows MBCS	StringCbCopy/StringCbCopyEx or StringCbCopyA/StringCbCopyExA
Microsoft Windows Unicode	StringCbCopy/StringCbCopyEx or StringCbCopyW/StringCbCopyExW
Microsoft Windows Generic	StringCbCopy/StringCbCopyEx

Windows Safe String Functions