RtlStringVPrintfWorkerA - NtDoc

#ifndef _NTSTRSAFE_H_INCLUDED_

NTSTRSAFEWORKERDDI
RtlStringVPrintfWorkerA(
    _Out_writes_(cchDest) _Always_(_Post_z_) NTSTRSAFE_PSTR pszDest,
    _In_ _In_range_(1, NTSTRSAFE_MAX_CCH) size_t cchDest,
    _Always_(_Out_opt_ _Deref_out_range_(<=, cchDest - 1)) size_t* pcchNewDestLength,
    _In_ _Printf_format_string_ NTSTRSAFE_PCSTR pszFormat,
    _In_ va_list argList);

#endif
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#ifndef _NTSTRSAFE_H_INCLUDED_
// Below here are the worker functions that actually do the work
#if defined(NTSTRSAFE_LIB_IMPL) || !defined(NTSTRSAFE_LIB)

NTSTRSAFEWORKERDDI
    RtlStringVPrintfWorkerA(
            _Out_writes_(cchDest) _Always_(_Post_z_) NTSTRSAFE_PSTR pszDest,
            _In_ _In_range_(1, NTSTRSAFE_MAX_CCH) size_t cchDest,
            _Always_(_Out_opt_ _Deref_out_range_(<=, cchDest - 1)) size_t* pcchNewDestLength,
            _In_ _Printf_format_string_ NTSTRSAFE_PCSTR pszFormat,
            _In_ va_list argList)
{
    NTSTATUS status = STATUS_SUCCESS;
    int iRet;
    size_t cchMax;
    size_t cchNewDestLength = 0;

    // leave the last space for the null terminator
    cchMax = cchDest - 1;

#if (NTSTRSAFE_USE_SECURE_CRT == 1) && !defined(NTSTRSAFE_LIB_IMPL)
    iRet = _vsnprintf_s(pszDest, cchDest, cchMax, pszFormat, argList);
#else
#pragma warning(push)
#pragma warning(disable: __WARNING_BANNED_API_USAGE)// "STRSAFE not included"
    iRet = _vsnprintf(pszDest, cchMax, pszFormat, argList);
#pragma warning(pop)
#endif
    // ASSERT((iRet < 0) || (((size_t)iRet) <= cchMax));

    if ((iRet < 0) || (((size_t)iRet) > cchMax))
    {
        // need to null terminate the string
        pszDest += cchMax;
        *pszDest = '\0';

        cchNewDestLength = cchMax;

        // we have truncated pszDest
        status = STATUS_BUFFER_OVERFLOW;
    }
    else if (((size_t)iRet) == cchMax)
    {
        // need to null terminate the string
        pszDest += cchMax;
        *pszDest = '\0';

        cchNewDestLength = cchMax;
    }
    else
    {
        cchNewDestLength = (size_t)iRet;
    }

    if (pcchNewDestLength)
    {
        *pcchNewDestLength = cchNewDestLength;
    }

    return status;
}

#endif
#endif
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#ifndef _NTSTRSAFE_H_INCLUDED_
// Do not call these functions, they are worker functions for internal use within this file
#ifdef DEPRECATE_SUPPORTED
// ...
#else

#define RtlStringVPrintfWorkerA            RtlStringVPrintfWorkerA_instead_use_StringCchVPrintfA_or_StringCbVPrintfA

#endif
#endif
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