StringCchVPrintf (Windows CE 5.0)
Developing an Application > Safe String Functions > Safe String Reference > StrSafe.h Character-Count Functions
This function is a replacement for vsprintf. It accepts a format string and its arguments, provided as a va_list, and returns a formatted string.
The size, in characters, of the destination buffer is provided to the function to ensure that StringCchVPrintf does not write past the end of this buffer.
HRESULT StringCchVPrintf( LPTSTR pszDest, size_t cchDest, LPCTSTR pszFormat, va_list argList);
Parameters
pszDest
[out] Pointer to a buffer that receives the formatted, null-terminated string created from pszFormat and argList.cchDest
[in] Size of the destination buffer, in characters.This value must be sufficiently large to accommodate the final formatted string plus 1 to account for the terminating null character.
The maximum number of characters allowed is STRSAFE_MAX_CCH.
pszFormat
[in] Pointer to a buffer containing a printf-style format string.This string must be null-terminated.
argList
[in] A va_list containing the arguments to be inserted into pszFormat.
Return Value
This function returns an HRESULT, as opposed to vsprintf, which returns the number of characters written.
It is strongly recommended that you use the SUCCEEDED and FAILED macros to test the return value of this function.
| Value | Description |
|---|---|
| S_OK | There was sufficient space for the result to be copied to pszDest without truncation and the buffer is null-terminated. |
| STRSAFE_E_INVALID_PARAMETER | The value in cchDest is 0 or larger than STRSAFE_MAX_CCH. |
| STRSAFE_E_INSUFFICIENT_BUFFER | The copy operation failed due to insufficient buffer space.
The destination buffer contains a truncated, null-terminated version of the intended result. Where truncation is acceptable, this is not necessarily a failure condition. |
Remarks
StringCchVPrintf provides additional processing for proper buffer handling in your code.
Poor buffer handling is implicated in many security issues that involve buffer overruns. StringCchVPrintf always null-terminates a nonzero-length destination buffer.
For more information on va_lists, see the conventions defined in Stdarg.h.
StringCchVPrintf can be used in its generic form, or specifically as StringCchVPrintfA (for ANSI strings) or StringCchVPrintfW (for Unicode strings). The form to use is determined by your data.
| String data type | String literal | Function |
|---|---|---|
| char | "string" | StringCchVPrintfA |
| TCHAR | TEXT("string") | StringCchVPrintf |
| WCHAR | L"string" | StringCchVPrintfW |
StringCchVPrintf and its ANSI and Unicode variants are replacements for these functions:
If the strings pointed to by pszDest, pszFormat, or argument strings overlap, behavior is undefined.
Neither pszFormat nor pszDest should be NULL.
If you require the handling of null string pointer values, see StringCchVPrintfEx.
Requirements
OS Versions: Windows CE 5.0 and later.
Header: strsafe.h.
Link Library: strsafe.lib.
See Also
StringCbVPrintf | StringCchVPrintfEx | StringCchPrintf
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