RtlStringCbVPrintfA - NtDoc

#ifndef _NTSTRSAFE_H_INCLUDED_
#ifndef NTSTRSAFE_LIB_IMPL
#ifndef NTSTRSAFE_NO_CB_FUNCTIONS

/*++

  NTSTATUS
  RtlStringCbVPrintf(
  _Out_writes_bytes_(cbDest) _Always_(_Post_z_) LPTSTR  pszDest,
  _In_ size_t  cbDest,
  _In_ _Printf_format_string_ LPCTSTR pszFormat,
  _In_ va_list argList
  );

  Routine Description:

  This routine is a safer version of the C built-in function 'vsprintf'.
  The size of the destination buffer (in bytes) is a parameter and
  this function will not write past the end of this buffer and it will
  ALWAYS null terminate the destination buffer (unless it is zero length).

  This function returns an NTSTATUS value, and not a pointer.  It returns
  STATUS_SUCCESS if the string was printed without truncation and null terminated,
  otherwise it will return a failure code. In failure cases it will return
  a truncated version of the ideal result.

Arguments:

pszDest     -  destination string

cbDest      -  size of destination buffer in bytes
length must be sufficient to hold the resulting formatted
string, including the null terminator.

pszFormat   -  format string which must be null terminated

argList     -  va_list from the variable arguments according to the
stdarg.h convention

Notes:
Behavior is undefined if destination, format strings or any arguments
strings overlap.

pszDest and pszFormat should not be NULL.  See RtlStringCbVPrintfEx if you
require the handling of NULL values.


Return Value:

STATUS_SUCCESS -   if there was sufficient space in the dest buffer for
the resultant string and it was null terminated.

failure        -   you can use the macro NTSTATUS_CODE() to get a win32
error code for all hresult failure cases

STATUS_BUFFER_OVERFLOW /
NTSTATUS_CODE(status) == ERROR_INSUFFICIENT_BUFFER
-   this return value is an indication that the print
operation failed due to insufficient space. When this
error occurs, the destination buffer is modified to
contain a truncated version of the ideal result and is
null terminated. This is useful for situations where
truncation is ok.

It is strongly recommended to use the NT_SUCCESS() macro to test the
return value of this function

--*/


NTSTRSAFEDDI
    RtlStringCbVPrintfA(
            _Out_writes_bytes_(cbDest) _Always_(_Post_z_) NTSTRSAFE_PSTR pszDest,
            _In_ size_t cbDest,
            _In_ _Printf_format_string_ NTSTRSAFE_PCSTR pszFormat,
            _In_ va_list argList)
{
    NTSTATUS status;
    size_t cchDest = cbDest / sizeof(char);

    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
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