RtlStringCchVPrintfA - NtDoc

Native API online documentation, based on the System Informer (formerly Process Hacker) phnt headers 
#ifndef _NTSTRSAFE_H_INCLUDED_
#ifndef NTSTRSAFE_LIB_IMPL
#ifndef NTSTRSAFE_NO_CCH_FUNCTIONS

NTSTRSAFEDDI
    RtlStringCchVPrintfA(
            _Out_writes_(cchDest) _Always_(_Post_z_) NTSTRSAFE_PSTR pszDest,
            _In_ size_t cchDest,
            _In_ _Printf_format_string_ NTSTRSAFE_PCSTR pszFormat,
            _In_ va_list argList)
{
    NTSTATUS status;

    status = RtlStringValidateDestA(pszDest, cchDest, NTSTRSAFE_MAX_CCH);

    if (NT_SUCCESS(status))
    {
        status = RtlStringVPrintfWorkerA(pszDest,
                cchDest,
                NULL,
                pszFormat,
                argList);
    }
    else if (cchDest > 0)
    {
        *pszDest = '\0';
    }

    return status;
}

#endif
#endif
#endif

View code on GitHub
// ntstrsafe.h

NTSTRSAFEDDI RtlStringCchVPrintfA(
  [out] NTSTRSAFE_PSTR  pszDest,
  [in]  size_t          cchDest,
  [in]  NTSTRSAFE_PCSTR pszFormat,
  [in]  va_list         argList
);
View the official Windows Driver Kit DDI reference

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Windows Driver Kit DDI reference (nf-ntstrsafe-rtlstringcchvprintfa)

RtlStringCchVPrintfA function

Description

The RtlStringCchVPrintfW and RtlStringCchVPrintfA functions create a character-counted text string, with formatting that is based on supplied formatting information.

Parameters

pszDest [out]

A pointer to a caller-supplied buffer that receives a formatted, null-terminated string. The function creates this string from both the formatting string that is supplied by pszFormat and the arguments supplied by argList.

cchDest [in]

The size of the destination buffer, in characters. The buffer must be large enough to contain the formatted string plus the terminating null character. The maximum number of characters allowed is NTSTRSAFE_MAX_CCH.

pszFormat [in]

A pointer to a null-terminated text string that contains printf-styled formatting directives.

argList [in]

A va_list-typed argument list. Arguments contained in the argument list will be interpreted by using the formatting string that is supplied by pszFormat.

Return value

The function returns one of the NTSTATUS values that are listed in the following table. For information about how to test NTSTATUS values, see Using NTSTATUS Values.

Return code Description
STATUS_SUCCESS This success status means source data was present, the output string was created without truncation, and the resultant destination buffer is null-terminated.
STATUS_BUFFER_OVERFLOW This warning status means the operation did not complete due to insufficient space in the destination buffer. The destination buffer contains a truncated version of the created string.
STATUS_INVALID_PARAMETER This error status means the function received an invalid input parameter. For more information, see the following paragraph.

The function returns the STATUS_INVALID_PARAMETER value when:

* The value in cchDest is larger than the maximum buffer size.
* The destination buffer was already full.
* A NULL pointer was present.
* The destination buffer length was zero, but a nonzero length source string was present.

Remarks

RtlStringCchVPrintfW and RtlStringCchVPrintfA should be used instead of the following functions:

All of these functions accept a format string and its arguments, which are provided as a va_list-typed argument list, and return a formatted string. RtlStringCchVPrintfW and RtlStringCchVPrintfA receive the size, in characters, of the destination buffer to ensure that the functions do not write past the end of the buffer.

For more information about va_list-typed argument lists, see the Microsoft Windows SDK documentation.

Use RtlStringCchVPrintfW to handle Unicode strings and RtlStringCchVPrintfA to handle ANSI strings. The form you use depends on your data, as shown in the following table.

String data type String literal Function
WCHAR L"string" RtlStringCchVPrintfW
char "string" RtlStringCchVPrintfA

If pszDest and pszFormat point to overlapping strings, or if any argument strings overlap, the behavior of the function is undefined.

Neither pszFormat nor pszDest can be NULL. If you need to handle NULL string pointer values, use RtlStringCchVPrintfEx.

For more information about the safe string functions, see Using Safe String Functions.

See also

RtlStringCbVPrintf

RtlStringCchPrintf

RtlStringCchVPrintfEx

View the official Windows Driver Kit DDI reference

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