StringCchVPrintfA function (strsafe.h)
Writes formatted data to the specified string using a pointer to a list of arguments. The size of the destination buffer is provided to the function to ensure that it does not write past the end of this buffer.
StringCchVPrintf is a replacement for the following functions:
Syntax
STRSAFEAPI StringCchVPrintfA(
[out] STRSAFE_LPSTR pszDest,
[in] size_t cchDest,
[in] STRSAFE_LPCSTR pszFormat,
[in] va_list argList
);
Parameters
[out] pszDest
Type: LPTSTR
The destination buffer, which receives the formatted, null-terminated string created from pszFormat and argList.
[in] cchDest
Type: size_t
The 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.
[in] pszFormat
Type: LPCTSTR
The format string. This string must be null-terminated. For more information, see Format Specification Syntax.
[in] argList
Type: va_list
The arguments to be inserted into the pszFormat string.
Return value
Type: HRESULT
This function can return one of the following values. It is strongly recommended that you use the SUCCEEDED and FAILED macros to test the return value of this function.
| Return code | Description |
|---|---|
|
There was sufficient space for the result to be copied to pszDest without truncation and the buffer is null-terminated. |
|
The value in cchDest is either 0 or larger than STRSAFE_MAX_CCH. |
|
The copy operation failed due to insufficient buffer space. The destination buffer contains a truncated, null-terminated version of the intended result. In situations where truncation is acceptable, this may not necessarily be seen as a failure condition. |
Note that this function returns an HRESULT value, unlike the functions that it replaces.
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.
Behavior is undefined if the strings pointed to by pszDest, pszFormat, or any argument strings overlap.
Neither pszFormat nor pszDest should be NULL. See StringCchVPrintfEx if you require the handling of null string pointer values.
StringCchVPrintf can be used in its generic form, or in its more specific forms. The data type of the string determines the form of this function that you should use, as shown in the following table.
| String Data Type | String Literal | Function |
|---|---|---|
| char | "string" | StringCchVPrintfA |
| TCHAR | TEXT("string") | StringCchVPrintf |
| WCHAR | L"string" | StringCchVPrintfW |
Note
The strsafe.h header defines StringCchVPrintf as an alias that automatically selects the ANSI or Unicode version of this function based on the definition of the UNICODE preprocessor constant. Mixing usage of the encoding-neutral alias with code that is not encoding-neutral can lead to mismatches that result in compilation or runtime errors. For more information, see Conventions for Function Prototypes.
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client | Windows XP with SP2 [desktop apps | UWP apps] |
| Minimum supported server | Windows Server 2003 with SP1 [desktop apps | UWP apps] |
| Target Platform | Windows |
| Header | strsafe.h |
See also
Reference