C / C++ / MFC

Unresolved extern "dwTlsIndex" exported function in dll

17-Sep-19 22:40

True, but I expect that in this case the compiler will optimze away the double initialization. All that remains is a little bit of extra code that, while not needed, serves to clarify that these members are indeed properly initialized - no matter what types these members really are.

Moreover, if the types happen to change in the future, it's safer not to rely on them being initialized by default.

It's similar to soem C++ keywords, like override: at the time you add it to your code, it doesn't serve any purpose but documentation. But if the virtual base method gets changed in the future, it's safer to use the override keyword because then the compiler will complain if you don't also adapt your override method(s).

GOTOs are a bit like wire coat hangers: they tend to breed in the darkness, such that where there once were few, eventually there are many, and the program's architecture collapses beneath them. (Fran Poretto)

ForNow17-Sep-19 2:41

Re: Unresolved extern "dwTlsIndex" exported function in dll

17-Sep-19 2:41

Hi
I have a c DLL. the Dllmain and the exported function(s) are in different source files. Since the exported function need the value of the variable dwTlsindex. I decalre as an extern

I both define it and declare it in DllMain

C++

extern DWORD dwTlsIndex;
static DWORD dwTlsIndex;
BOOL APIENTRY DllMain( HMODULE hModule,
                       DWORD  ul_reason_for_call,
                       LPVOID lpReserved
                     )

in the exported function the following is the definition I know I have used the extern storage specifier with out any problem many times maybe there is something different because this is a DLL as the linker cant resolve dwTlsIndex

C++

#else

	 __declspec(dllexport) void opendata(char *);
#endif

	 extern DWORD dwTlsIndex;
	
	 void opendata(char *filename)
	 {
		 typedef void *(DLL_FN)(char *);

CPallini17-Sep-19 3:19

CPallini

17-Sep-19 3:19

Quote:
extern DWORD dwTlsIndex;
static DWORD dwTlsIndex;

You should just write

DWORD dwTlsIndex;

because:

You don't need the extern declaration in the file that defines the variable.
The static keyword makes the variable having file-scope (link failure).

Re: Unresolved extern "dwTlsIndex" exported function in dll

ForNow17-Sep-19 3:42

Re: Unresolved extern "dwTlsIndex" exported function in dll Changed DLLMAIN.CPP to DLLMAIN.C clean link

17-Sep-19 3:42

Tried it still getting unresolved maybe something I have to do in my project

ForNow17-Sep-19 8:02

manual kerning with winAPI

17-Sep-19 8:02

thanks

Alexander Kindel15-Sep-19 21:38

Alexander Kindel

15-Sep-19 21:38

I'm working on a program that needs to be able to detect when the user has clicked on a font glyph - the actual filled part of the glyph, not just its bounding box. I'm trying to do this by analyzing the outline produced by GetGlyphOutlineW for each glyph. In this program, most glyphs are drawn by passing a single codepoint to TextOutW, but there is one case where I pass multiple codepoints. I understand that in this case, I have to take kerning into account in order for my analysis of the glyph outlines to match up with what TextOutW draws. Keeping in mind that I want to stick to C API's since the program is actually in another language and calling winAPI through a foreign function interface, are the GetKerningPairs functions the only way to get the necessary information to account for the kerning? In particular, do I have to iterate through all the kerning pairs for the entire font and check each one for whether it matches the pair I'm trying to kern rather than, say, asking Windows for the kerning pair for a particular pair of characters, if one exists?

typedef for a function for different platforms

ForNow13-Sep-19 3:29

13-Sep-19 3:29

Hi
I have the same piece of code running on Windows and Zos (mainframe) is it possible to typedef the read
I am getting a compile error saying before SYSREAD there should be a ";"

thanks

I.e.

C++

#ifdef ZOS
 size_t fread(void * __restrict__buffer, size_t size, size_t count, FILE * __restrict__stream) SYSREAD;
#ELSE
   typedef BOOL ReadFileEx(HANDLE, LPVOID, DWORD, LPOVERLAPPED, LPOVERLAPPED_COMPLETION_ROUTINE) SYSREAD;
#endif
	 HANDLE hFile;

Stefan_Lang13-Sep-19 3:58

13-Sep-19 3:58

That's not a valid typedef, and you cannot resolve your problem in this manner. You could create a typedef for a function that takes a certain list of parameters, and returns BOOL, but that would not then be tied to the function ReadFileEx as appears to be your intent.

(and, on a sidenote, I'm not sure the compiler will eat that capitalized #ELSE)

Just provide an adapter function for this purpose:

C++

#ifdef ZOS
...
#else
BOOL SYSREAD(...)
{
    return ReadFileEx(...);
}
#endif

P.S.: NOw that I've reread the code you've written, I am no longer sure what it's supposed to do. I still think that an adapter function is what you need, but the syntax you've used above doesn't appear to make any sense under that assumption.

So, if you intended something else, maybe you should point out what that code should do, or better yet, show a line of code or two that uses SYSREAD in the intended manner.

ForNow13-Sep-19 4:36

13-Sep-19 4:36

thanks

Richard MacCutchan13-Sep-19 3:59

Richard MacCutchan

13-Sep-19 3:59

You forgot the typedef keyword.

ForNow13-Sep-19 4:36

13-Sep-19 4:36

thanks

Error 12029 WinHTTP

Diprom12-Sep-19 22:36

Diprom

12-Sep-19 22:36

Hello. I am applying a demo project in which I use winhttp asynchronously via callback.
After cyclic sending of n-requests, error 12029 is often generated. If you insert Sleep in the code, then
all words go away without errors. I would like to understand how you can without sleep. Made specifically so that later
tie the call to the queue.

C++

#include "stdafx.h"
#include <windows.h>
#include <winhttp.h>
#include <stdio.h>
#pragma comment(lib,"winhttp")



// Context value structure.
typedef struct {
    HINTERNET   hSession;               // HTTP Session
    HINTERNET   hConnect;               // Connection handle
    HINTERNET   hRequest;               // Resource request handle
    DWORD       dwSize;                 // Size of the latest data block
    DWORD       dwTotalSize;            // Size of the total data
    LPSTR       lpBuffer;               // Buffer for storing read data
    char*       SendBuffer;             // Send buffer
    wchar_t*    URL;                    // URL
    int         Resend;                 // flag to resend
    DWORD       SendTimeout;            // send timeout
    DWORD       ReceiveTimeout;         // receive timeout
    DWORD       ConnectTimeout;         // connect timeout
    DWORD       ResolveTimeout;         // resolve timeout
    bool        IsBadRequest;           // bad request complete
    WINHTTP_STATUS_CALLBACK pCallback;  //callback

} REQUEST_CONTEXT;


int CounterGood = 0;
int CounterBad = 0;

// This macro returns the constant name in a string.
#define CASE_OF(constant)   case constant: return (L# constant)

LPCWSTR GetApiErrorString(DWORD dwResult)
{
    // Return the error result as a string so that the
    // name of the function causing the error can be displayed.
    switch(dwResult)
    {
        CASE_OF( API_RECEIVE_RESPONSE );
        CASE_OF( API_QUERY_DATA_AVAILABLE );
        CASE_OF( API_READ_DATA );
        CASE_OF( API_WRITE_DATA );
        CASE_OF( API_SEND_REQUEST );
    }
    return L"Unknown function";
}



void Cleanup (REQUEST_CONTEXT *cpContext)
{
   
    if (!cpContext)
    {
        return;
    }
    if (cpContext->IsBadRequest)
        CounterBad++;
    else
        CounterGood++;
    WCHAR szBuffer[256];
    // Set the memo to indicate a closed handle.
    swprintf(szBuffer,sizeof(szBuffer), L"Cleanup");
    //printf("%ws",szBuffer);
    if (cpContext->hRequest)
    {
        swprintf(szBuffer, sizeof(szBuffer), L">WinHttpSetStatusCallback NULL");
        //printf("%ws",szBuffer);
        WinHttpSetStatusCallback(cpContext->hRequest, NULL, NULL, NULL);
        swprintf(szBuffer, sizeof(szBuffer), L"<WinHttpSetStatusCallback NULL");
        //printf("%ws",szBuffer);

        swprintf(szBuffer, sizeof(szBuffer), L">WinHttpCloseHandle hRequest (%X)", (unsigned int)cpContext->hRequest);
        //printf("%ws",szBuffer);
        WinHttpCloseHandle(cpContext->hRequest);
        swprintf(szBuffer, sizeof(szBuffer), L"<WinHttpCloseHandle");
        //printf("%ws",szBuffer);
        cpContext->hRequest = NULL;
    }

    if (cpContext->hConnect)
    {
        swprintf(szBuffer, sizeof(szBuffer), L">WinHttpCloseHandle hConnect (%X)", (unsigned int)cpContext->hConnect);
        //printf("%ws",szBuffer);
        WinHttpCloseHandle(cpContext->hConnect);
        swprintf(szBuffer, sizeof(szBuffer), L"<WinHttpCloseHandle");
        //printf("%ws",szBuffer);
        cpContext->hConnect = NULL;
    }

    if (cpContext->hSession)
    {
        swprintf(szBuffer, sizeof(szBuffer), L">WinHttpCloseHandle hConnect (%X)", (unsigned int)cpContext->hSession);
        //printf("%ws",szBuffer);
        WinHttpCloseHandle(cpContext->hSession);
        swprintf(szBuffer, sizeof(szBuffer), L"<WinHttpCloseHandle");
        //printf("%ws",szBuffer);
        cpContext->hSession = NULL;
    }

    delete [] cpContext->lpBuffer;
    cpContext->lpBuffer = NULL;

    if (cpContext->SendBuffer)
    {
        delete cpContext->SendBuffer;
        cpContext->SendBuffer = NULL;
    }

    if (cpContext && cpContext->URL)
    {
        delete cpContext->URL;
        cpContext->URL = NULL;

    }  
    delete cpContext;
    cpContext = NULL;
}


// Forward declaration.
void __stdcall AsyncCallback(HINTERNET, DWORD_PTR, DWORD, LPVOID, DWORD);

BOOL SendRequest(REQUEST_CONTEXT *cpContext)
{
    if (!cpContext) return FALSE;
    if (!cpContext->URL) return FALSE;
    WCHAR szHost[256];
    DWORD dwOpenRequestFlag = 0;
    URL_COMPONENTS urlComp;
    BOOL fRet = FALSE;
    WCHAR szBuffer[256];

    // Initialize URL_COMPONENTS structure.
    ZeroMemory(&urlComp, sizeof(urlComp));
    urlComp.dwStructSize = sizeof(urlComp);

    // Use allocated buffer to store the Host Name.
    urlComp.lpszHostName        = szHost;
    urlComp.dwHostNameLength    = sizeof(szHost) / sizeof(szHost[0]);

    // Set non zero lengths to obtain pointer to the URL Path.
    /* note: if we threat this pointer as a NULL terminated string
            this pointer will contain Extra Info as well. */
    urlComp.dwUrlPathLength = -1;

    // Crack HTTP scheme.
    urlComp.dwSchemeLength = -1;


    swprintf( szBuffer, sizeof(szBuffer), L">Calling WinHttpCrackURL for %s", cpContext->URL);
    //printf("%wsn",szBuffer);

    // Crack the URL.
    if (!WinHttpCrackUrl(cpContext->URL, 0, 0, &urlComp))
    {
        swprintf(szBuffer, sizeof(szBuffer), L"< WinHttpCrackUrl failed : %X", GetLastError());
        //printf("%wsn",szBuffer);
        goto cleanup;
    }

    // Install the status callback function.
   
    if (cpContext->pCallback == NULL)
    {
        swprintf(szBuffer, sizeof(szBuffer), L">Calling WinHttpSetStatusCallback with WINHTTP_CALLBACK_FLAG_ALL_NOTIFICATIONS");
        //printf("%wsn",szBuffer);
        cpContext->pCallback = WinHttpSetStatusCallback(cpContext->hSession,
            (WINHTTP_STATUS_CALLBACK)AsyncCallback,
            WINHTTP_CALLBACK_FLAG_ALL_NOTIFICATIONS,
            NULL);
    }
    // note: On success WinHttpSetStatusCallback returns the previously defined callback function.
    // Here it should be NULL
    if (cpContext->pCallback == WINHTTP_INVALID_STATUS_CALLBACK)
    {
        swprintf(szBuffer, sizeof(szBuffer), L"< WinHttpSetStatusCallback WINHTTP_INVALID_STATUS_CALLBACK");
        //printf("%wsn",szBuffer);
        goto cleanup;
    }

    swprintf(szBuffer, sizeof(szBuffer), L"< WinHttpSetStatusCallback succeeded");
    //printf("%wsn",szBuffer);

    swprintf(szBuffer, sizeof(szBuffer), L">Calling WinHttpConnect for host %s and port %d", szHost, urlComp.nPort);
    //printf("%wsn",szBuffer);

    // Open an HTTP session.
    cpContext->hConnect = WinHttpConnect(cpContext->hSession, szHost, urlComp.nPort, 0);
    if (NULL == cpContext->hConnect)
    {
        swprintf(szBuffer, sizeof(szBuffer), L"< WinHttpConnect failed : %X", GetLastError());
        //printf("%wsn",szBuffer);
        goto cleanup;
    }
    swprintf(szBuffer, sizeof(szBuffer), L"< WinHttpConnect  succeeded");

    //printf("%wsn",szBuffer);

    swprintf(szBuffer, sizeof(szBuffer), L"> Calling WinHttpGetIEProxyConfigForCurrentUser");
    //printf("%wsn",szBuffer);

    // Prepare OpenRequest flag
    dwOpenRequestFlag = (INTERNET_SCHEME_HTTPS == urlComp.nScheme) ?
                            WINHTTP_FLAG_SECURE : 0;

    swprintf(szBuffer, sizeof(szBuffer), L">Calling WinHttpOpenRequest");
    //printf("%wsn",szBuffer);

    // Open a "GET" request.
    cpContext->hRequest = WinHttpOpenRequest(cpContext->hConnect,
                                        L"GET", urlComp.lpszUrlPath,
                                        NULL, WINHTTP_NO_REFERER,
                                        WINHTTP_DEFAULT_ACCEPT_TYPES,
                                        dwOpenRequestFlag);

    if (cpContext->hRequest == 0)
    {
        swprintf(szBuffer, sizeof(szBuffer), L"< WinHttpOpenRequest failed : %X", GetLastError());
        //printf("%wsn",szBuffer);
        goto cleanup;
    }
    swprintf(szBuffer, sizeof(szBuffer), L"< WinHttpOpenRequest succeeded");
    //printf("%wsn",szBuffer);

    swprintf( szBuffer, sizeof(szBuffer), L"> Calling WinHttpSendRequest");
    //printf("%wsn",szBuffer);

    if (cpContext->Resend == 0)
    if (!WinHttpSetTimeouts(cpContext->hRequest,cpContext->ResolveTimeout,cpContext->ConnectTimeout,cpContext->SendTimeout,cpContext->ReceiveTimeout))
    {
        swprintf(szBuffer, sizeof(szBuffer), L"< WinHttpSetTimeouts failed : %X", GetLastError());
        goto cleanup;
    }

    DWORD f = 0;
    if (cpContext->SendBuffer)
    {
        f = strlen(cpContext->SendBuffer);
    }
    swprintf( szBuffer, sizeof(szBuffer), L"> Calling WinHttpSendRequest");

    // Send the request.
    if (!WinHttpSendRequest(cpContext->hRequest, WINHTTP_NO_ADDITIONAL_HEADERS, 0, cpContext->SendBuffer,f,f, (DWORD_PTR)cpContext))
    {
        swprintf(szBuffer, sizeof(szBuffer), L"< WinHttpSendRequest failed : %X", GetLastError());
        goto cleanup;
    }

    fRet = TRUE;

cleanup:

    if (fRet == FALSE)
    {
        WCHAR szError[256];

        // Set the error message.
        swprintf(szError, sizeof(szBuffer), L"%s failed with error %d", szBuffer, GetLastError());
        //printf("%wsn",szBuffer);
        // Cleanup handles.
        Cleanup(cpContext);
                   
        // Display the error message.
        //printf("%wsn",szError);

    }
               
    return fRet;
}
 


BOOL Header(REQUEST_CONTEXT *cpContext)
{
    DWORD dwSize=0;
    LPVOID lpOutBuffer = NULL;
    WCHAR szBuffer[256];

    // Set the state memo.
    swprintf(szBuffer, sizeof(szBuffer), L">Calling WinHttpQueryHeaders");
    //SendDlgItemMessage(cpContext->hWindow, IDC_CBLIST, LB_ADDSTRING, 0, (LPARAM)szBuffer);

    // Use HttpQueryInfo to obtain the size of the buffer.
    if (!WinHttpQueryHeaders( cpContext->hRequest,
                              WINHTTP_QUERY_RAW_HEADERS_CRLF,
                              WINHTTP_HEADER_NAME_BY_INDEX, NULL, &dwSize, WINHTTP_NO_HEADER_INDEX))
    {
        // An ERROR_INSUFFICIENT_BUFFER is expected because you
        // are looking for the size of the headers.  If any other
        // error is encountered, display error information.
        DWORD dwErr = GetLastError();
        if (dwErr != ERROR_INSUFFICIENT_BUFFER)
        {
 
            swprintf( szBuffer, sizeof(szBuffer), L"Error %d encountered.", dwErr);
            //SendDlgItemMessage(cpContext->hWindow, IDC_CBLIST, LB_ADDSTRING, 0, (LPARAM)szBuffer);
            //SetDlgItemText( cpContext->hWindow, cpContext->nResource, szBuffer);
            return FALSE;
        }
    }
   
    // Allocate memory for the buffer.
    lpOutBuffer = new WCHAR[dwSize];

    // Use HttpQueryInfo to obtain the header buffer.
    if(WinHttpQueryHeaders( cpContext->hRequest,
                            WINHTTP_QUERY_RAW_HEADERS_CRLF,
                            WINHTTP_HEADER_NAME_BY_INDEX, lpOutBuffer, &dwSize, WINHTTP_NO_HEADER_INDEX))
    {
       // SetDlgItemText( cpContext->hWindow, cpContext->nHeader, (LPWSTR)lpOutBuffer);
    }

    // Free the allocated memory.
    delete [] lpOutBuffer;

    return TRUE;
}


BOOL QueryData(REQUEST_CONTEXT *cpContext)
{
    WCHAR szBuffer[256];
    // Set the state memo.
    swprintf( szBuffer, sizeof(szBuffer), L">Calling WinHttpQueryDataAvailable");
       
    // Chech for available data.
    if (WinHttpQueryDataAvailable(cpContext->hRequest, NULL) == FALSE)
    {
        // If a synchronous error occured, display the error.  Otherwise
        // the query is successful or asynchronous.
        DWORD dwErr = GetLastError();
        swprintf( szBuffer, sizeof(szBuffer), L"Error %d encountered.", dwErr);
        //SendDlgItemMessage(cpContext->hWindow, IDC_CBLIST, LB_ADDSTRING, 0, (LPARAM)szBuffer);
        //SetDlgItemText( cpContext->hWindow, cpContext->nResource, szBuffer);
        return FALSE;
    }
    return TRUE;
}


void TransferAndDeleteBuffers(REQUEST_CONTEXT *cpContext, LPSTR lpReadBuffer, DWORD dwBytesRead)
{
    cpContext->dwSize = dwBytesRead;

    if(!cpContext->lpBuffer)
    {
        // If there is no context buffer, start one with the read data.
        cpContext->lpBuffer = lpReadBuffer;
    }
    else
    {
        // Store the previous buffer, and create a new one big
        // enough to hold the old data and the new data.
        LPSTR lpOldBuffer = cpContext->lpBuffer;
        cpContext->lpBuffer = new char[cpContext->dwTotalSize + cpContext->dwSize];

        // Copy the old and read buffer into the new context buffer.
        memcpy(cpContext->lpBuffer, lpOldBuffer, cpContext->dwTotalSize);
        memcpy(cpContext->lpBuffer + cpContext->dwTotalSize, lpReadBuffer, cpContext->dwSize);

        // Free the memory allocated to the old and read buffers.
        delete [] lpOldBuffer;
        delete [] lpReadBuffer;
    }
   
    // Keep track of the total size.
    cpContext->dwTotalSize += cpContext->dwSize;
}
 

BOOL ReadData(REQUEST_CONTEXT *cpContext)
{
    LPSTR lpOutBuffer = new char[cpContext->dwSize+1];
    WCHAR szBuffer[256];
    ZeroMemory(lpOutBuffer, cpContext->dwSize+1);

    // Set the state memo.
    swprintf( szBuffer, sizeof(szBuffer), L">Calling WinHttpReadData with size %d", cpContext->dwSize);
    //SendDlgItemMessage(cpContext->hWindow, IDC_CBLIST, LB_ADDSTRING, 0, (LPARAM)szBuffer);

    // Read the available data.
    if (WinHttpReadData( cpContext->hRequest, (LPVOID)lpOutBuffer,
                          cpContext->dwSize, NULL) == FALSE)
    {
        // If a synchronous error occurred, display the error.  Otherwise
        // the read is successful or asynchronous.
        DWORD dwErr = GetLastError();
        swprintf( szBuffer, sizeof(szBuffer), L"WinHttpReadData Error %d encountered.", dwErr);
       // SetDlgItemText( cpContext->hWindow, cpContext->nResource, szBuffer);
        //SendDlgItemMessage(cpContext->hWindow, IDC_CBLIST, LB_ADDSTRING, 0, (LPARAM)szBuffer);
        delete [] lpOutBuffer;
        return FALSE;
    }
    swprintf(szBuffer, sizeof(szBuffer), L"<WinHttpReadData");
    //SendDlgItemMessage(cpContext->hWindow, IDC_CBLIST, LB_ADDSTRING, 0, (LPARAM)szBuffer);

    return TRUE;
}


//********************************************************************
//                                                   Status Callback  
//********************************************************************

void __stdcall AsyncCallback( HINTERNET hInternet, DWORD_PTR dwContext,
                              DWORD dwInternetStatus,
                              LPVOID lpvStatusInformation,
                              DWORD dwStatusInformationLength)
{
    REQUEST_CONTEXT *cpContext;
    WCHAR szBuffer[1024];
    cpContext = (REQUEST_CONTEXT*)dwContext;
    WINHTTP_ASYNC_RESULT *pAR;

    if (cpContext == NULL)
    {
        // this should not happen, but we are being defensive here
        return;
    }

    szBuffer[0] = 0;

    // Create a string that reflects the status flag.
    switch (dwInternetStatus)
    {
    case WINHTTP_CALLBACK_STATUS_CLOSING_CONNECTION:
        //Closing the connection to the server.The lpvStatusInformation parameter is NULL.
        swprintf(szBuffer, sizeof(szBuffer), L"CLOSING_CONNECTION (%d)",  dwStatusInformationLength);
        break;

    case WINHTTP_CALLBACK_STATUS_CONNECTED_TO_SERVER:
        //Successfully connected to the server.
        //The lpvStatusInformation parameter contains a pointer to an LPWSTR that indicates the IP address of the server in dotted notation.
        if (lpvStatusInformation)
        {
            swprintf(szBuffer, sizeof(szBuffer), L"CONNECTED_TO_SERVER (%s)",  (WCHAR *)lpvStatusInformation);
        }
        else
        {
            swprintf(szBuffer, sizeof(szBuffer), L"CONNECTED_TO_SERVER (%d)",  dwStatusInformationLength);
        }
        break;

    case WINHTTP_CALLBACK_STATUS_CONNECTING_TO_SERVER:
        //Connecting to the server.
        //The lpvStatusInformation parameter contains a pointer to an LPWSTR that indicates the IP address of the server in dotted notation.
        if (lpvStatusInformation)
        {
            swprintf(szBuffer, sizeof(szBuffer), L"CONNECTING_TO_SERVER (%s)",  (WCHAR *)lpvStatusInformation);
        }
        else
        {
            swprintf(szBuffer, sizeof(szBuffer), L"CONNECTING_TO_SERVER (%d)",  dwStatusInformationLength);
        }
        break;

    case WINHTTP_CALLBACK_STATUS_CONNECTION_CLOSED:
        //Successfully closed the connection to the server. The lpvStatusInformation parameter is NULL.
        swprintf(szBuffer, sizeof(szBuffer), L"CONNECTION_CLOSED (%d)",  dwStatusInformationLength);
        break;

    case WINHTTP_CALLBACK_STATUS_DATA_AVAILABLE:
        //Data is available to be retrieved with WinHttpReadData.The lpvStatusInformation parameter points to a DWORD that contains the number of bytes of data available.
        //The dwStatusInformationLength parameter itself is 4 (the size of a DWORD).

        cpContext->dwSize = *((LPDWORD)lpvStatusInformation);
       
        // If there is no data, the process is complete.
        if (cpContext->dwSize == 0)
        {
            swprintf(szBuffer, sizeof(szBuffer), L"DATA_AVAILABLE Number of bytes available : %d. All data has been read -> Displaying the data.", cpContext->dwSize);
            // All of the data has been read.  Display the data.
            if (cpContext->dwTotalSize)
            {
                // Convert the final context buffer to wide characters,
                // and display.
                LPWSTR lpWideBuffer = new WCHAR[cpContext->dwTotalSize + 1];
                MultiByteToWideChar(CP_ACP, MB_PRECOMPOSED,
                    cpContext->lpBuffer,
                    cpContext->dwTotalSize,
                    lpWideBuffer,
                    cpContext->dwTotalSize);
                lpWideBuffer[cpContext->dwTotalSize] = 0;
                /* note: in the case of binary data, only data upto the first null will be displayed */
                //SetDlgItemText(cpContext->hWindow, cpContext->nResource, lpWideBuffer);

                // Delete the remaining data buffers.
                delete[] lpWideBuffer;
                delete[] cpContext->lpBuffer;
                cpContext->lpBuffer = NULL;
            }

            // Close the request and connect handles for this context.
            Cleanup(cpContext);

        }
        else
        {
            swprintf(szBuffer, sizeof(szBuffer), L"DATA_AVAILABLE Number of bytes available : %d. Reading next block of data", cpContext->dwSize);
            // Otherwise, read the next block of data.
            if (ReadData(cpContext) == FALSE)
            {
                swprintf(szBuffer, sizeof(szBuffer), L"DATA_AVAILABLE Number of bytes available : %d. ReadData returning FALSE", cpContext->dwSize);
                Cleanup(cpContext);
            }
        }
        break;

    case WINHTTP_CALLBACK_STATUS_HANDLE_CREATED:
        //An HINTERNET handle has been created. The lpvStatusInformation parameter contains a pointer to the HINTERNET handle.
        if (lpvStatusInformation)
        {
            swprintf(szBuffer, sizeof(szBuffer), L"HANDLE_CREATED : %X",  (unsigned int)lpvStatusInformation);
        }
        else
        {
            swprintf(szBuffer, sizeof(szBuffer), L"HANDLE_CREATED (%d)",  dwStatusInformationLength);
        }
        break;

    case WINHTTP_CALLBACK_STATUS_HANDLE_CLOSING:
        //This handle value has been terminated. The lpvStatusInformation parameter contains a pointer to the HINTERNET handle. There will be no more callbacks for this handle.
        if (lpvStatusInformation)
        {
            swprintf(szBuffer, sizeof(szBuffer), L"HANDLE_CLOSING : %X",  (unsigned int)lpvStatusInformation);
        }
        else
        {
            swprintf(szBuffer, sizeof(szBuffer), L"HANDLE_CLOSING (%d)",  dwStatusInformationLength);
        }
        break;

    case WINHTTP_CALLBACK_STATUS_HEADERS_AVAILABLE:
        //The response header has been received and is available with WinHttpQueryHeaders. The lpvStatusInformation parameter is NULL.
        swprintf(szBuffer, sizeof(szBuffer), L"HEADERS_AVAILABLE (%d)",  dwStatusInformationLength);
        Header(cpContext);

        // Initialize the buffer sizes.
        cpContext->dwSize = 0;
        cpContext->dwTotalSize = 0;

        // Begin downloading the resource.
        if (QueryData(cpContext) == FALSE)
        {
            Cleanup(cpContext);
        }
        break;

    case WINHTTP_CALLBACK_STATUS_INTERMEDIATE_RESPONSE:
        //Received an intermediate (100 level) status code message from the server.
        //The lpvStatusInformation parameter contains a pointer to a DWORD that indicates the status code.
        if (lpvStatusInformation)
        {
            swprintf(szBuffer, sizeof(szBuffer), L"INTERMEDIATE_RESPONSE Status code : %d",  *(DWORD*)lpvStatusInformation);
        }
        else
        {
            swprintf(szBuffer, sizeof(szBuffer), L"INTERMEDIATE_RESPONSE (%d)",  dwStatusInformationLength);
        }
        break;

    case WINHTTP_CALLBACK_STATUS_NAME_RESOLVED:
        //Successfully found the IP address of the server. The lpvStatusInformation parameter contains a pointer to a LPWSTR that indicates the name that was resolved.
        if (lpvStatusInformation)
        {
            swprintf(szBuffer, sizeof(szBuffer), L"NAME_RESOLVED : %s",  (WCHAR *)lpvStatusInformation);
        }
        else
        {
            swprintf(szBuffer, sizeof(szBuffer), L"NAME_RESOLVED (%d)",  dwStatusInformationLength);
        }
        break;


    case WINHTTP_CALLBACK_STATUS_READ_COMPLETE:
        //Data was successfully read from the server. The lpvStatusInformation parameter contains a pointer to the buffer specified in the call to WinHttpReadData.
        //The dwStatusInformationLength parameter contains the number of bytes read.
        //When used by WinHttpWebSocketReceive, the lpvStatusInformation parameter contains a pointer to a WINHTTP_WEB_SOCKET_STATUS structure,
        //  and the dwStatusInformationLength parameter indicates the size of lpvStatusInformation.

        swprintf(szBuffer, sizeof(szBuffer), L"READ_COMPLETE Number of bytes read : %d",  dwStatusInformationLength);

        // Copy the data and delete the buffers.

        if (dwStatusInformationLength != 0)
        {
            TransferAndDeleteBuffers(cpContext, (LPSTR)lpvStatusInformation, dwStatusInformationLength);

            // Check for more data.
            if (QueryData(cpContext) == FALSE)
            {
                Cleanup(cpContext);
            }
        }
        break;


    case WINHTTP_CALLBACK_STATUS_RECEIVING_RESPONSE:
        //Waiting for the server to respond to a request. The lpvStatusInformation parameter is NULL.
        swprintf(szBuffer, sizeof(szBuffer), L"RECEIVING_RESPONSE (%d)",  dwStatusInformationLength);
        break;

    case WINHTTP_CALLBACK_STATUS_REDIRECT:
        //An HTTP request is about to automatically redirect the request. The lpvStatusInformation parameter contains a pointer to an LPWSTR indicating the new URL.
        //At this point, the application can read any data returned by the server with the redirect response and can query the response headers. It can also cancel the operation by closing the handle

        if (lpvStatusInformation)
        {
            swprintf(szBuffer, sizeof(szBuffer), L"REDIRECT to %s",  (WCHAR *)lpvStatusInformation);
        }
        else
        {
            swprintf(szBuffer, sizeof(szBuffer), L"REDIRECT (%d)",  dwStatusInformationLength);
        }      
        break;

    case WINHTTP_CALLBACK_STATUS_REQUEST_ERROR:
        //An error occurred while sending an HTTP request.
        //The lpvStatusInformation parameter contains a pointer to a WINHTTP_ASYNC_RESULT structure. Its dwResult member indicates the ID of the called function and dwError indicates the return value.
        pAR = (WINHTTP_ASYNC_RESULT *)lpvStatusInformation;
        swprintf(szBuffer, sizeof(szBuffer), L"REQUEST_ERROR - error %d, result %s",  pAR->dwError, GetApiErrorString(pAR->dwResult));
        if (cpContext)

            cpContext->IsBadRequest = true;
        Cleanup(cpContext);
        break;

    case WINHTTP_CALLBACK_STATUS_REQUEST_SENT:
        //Successfully sent the information request to the server.
        //The lpvStatusInformation parameter contains a pointer to a DWORD indicating the number of bytes sent.
        if (lpvStatusInformation)
        {
            swprintf(szBuffer, sizeof(szBuffer), L"REQUEST_SENT Number of bytes sent : %d",  *(DWORD*)lpvStatusInformation);
        }
        else
        {
            swprintf(szBuffer, sizeof(szBuffer), L"REQUEST_SENT (%d)",  dwStatusInformationLength);
        }
        break;

    case WINHTTP_CALLBACK_STATUS_RESOLVING_NAME:
        //Looking up the IP address of a server name. The lpvStatusInformation parameter contains a pointer to the server name being resolved.
        if (lpvStatusInformation)
        {
            swprintf(szBuffer, sizeof(szBuffer), L"RESOLVING_NAME %s",  (WCHAR*)lpvStatusInformation);
        }
        else
        {
            swprintf(szBuffer, sizeof(szBuffer), L"RESOLVING_NAME (%d)",  dwStatusInformationLength);
        }
        break;

    case WINHTTP_CALLBACK_STATUS_RESPONSE_RECEIVED:
        //Successfully received a response from the server.
        //The lpvStatusInformation parameter contains a pointer to a DWORD indicating the number of bytes received.
        if (lpvStatusInformation)
        {
            swprintf(szBuffer, sizeof(szBuffer), L"RESPONSE_RECEIVED. Number of bytes : %d",  *(DWORD*)lpvStatusInformation);
        }
        else
        {
            swprintf(szBuffer, sizeof(szBuffer), L"RESPONSE_RECEIVED (%d)",  dwStatusInformationLength);
        }
        break;

    case WINHTTP_CALLBACK_STATUS_SECURE_FAILURE:
        //One or more errors were encountered while retrieving a Secure Sockets Layer (SSL) certificate from the server.
        /*If the dwInternetStatus parameter is WINHTTP_CALLBACK_STATUS_SECURE_FAILURE, this parameter can be a bitwise-OR combination of one or more of the following values:
            WINHTTP_CALLBACK_STATUS_FLAG_CERT_REV_FAILED
            Certification revocation checking has been enabled, but the revocation check failed to verify whether a certificate has been revoked.The server used to check for revocation might be unreachable.
            WINHTTP_CALLBACK_STATUS_FLAG_INVALID_CERT
            SSL certificate is invalid.
            WINHTTP_CALLBACK_STATUS_FLAG_CERT_REVOKED
            SSL certificate was revoked.
            WINHTTP_CALLBACK_STATUS_FLAG_INVALID_CA
            The function is unfamiliar with the Certificate Authority that generated the server's certificate.
            WINHTTP_CALLBACK_STATUS_FLAG_CERT_CN_INVALID
            SSL certificate common name(host name field) is incorrect, for example, if you entered www.microsoft.com and the common name on the certificate says www.msn.com.
            WINHTTP_CALLBACK_STATUS_FLAG_CERT_DATE_INVALID
            SSL certificate date that was received from the server is bad.The certificate is expired.
            WINHTTP_CALLBACK_STATUS_FLAG_SECURITY_CHANNEL_ERROR
            The application experienced an internal error loading the SSL libraries.
        */
        if (lpvStatusInformation)
        {
            swprintf(szBuffer, sizeof(szBuffer), L"SECURE_FAILURE (%d).",  *(DWORD*)lpvStatusInformation);
            if (*(DWORD*)lpvStatusInformation & WINHTTP_CALLBACK_STATUS_FLAG_CERT_REV_FAILED)  //1
            {
                wcscat_s(szBuffer, L"Revocation check failed to verify whether a certificate has been revoked.");
            }
            if (*(DWORD*)lpvStatusInformation & WINHTTP_CALLBACK_STATUS_FLAG_INVALID_CERT)  //2
            {
                wcscat_s(szBuffer, L"SSL certificate is invalid.");
            }
            if (*(DWORD*)lpvStatusInformation & WINHTTP_CALLBACK_STATUS_FLAG_CERT_REVOKED)  //4
            {
                wcscat_s(szBuffer, L"SSL certificate was revoked.");
            }
            if (*(DWORD*)lpvStatusInformation & WINHTTP_CALLBACK_STATUS_FLAG_INVALID_CA)  //8
            {
                wcscat_s(szBuffer, L"The function is unfamiliar with the Certificate Authority that generated the server's certificate.");
            }
            if (*(DWORD*)lpvStatusInformation & WINHTTP_CALLBACK_STATUS_FLAG_CERT_CN_INVALID)  //10
            {
                wcscat_s(szBuffer, L"SSL certificate common name(host name field) is incorrect");
            }
            if (*(DWORD*)lpvStatusInformation & WINHTTP_CALLBACK_STATUS_FLAG_CERT_DATE_INVALID)  //20
            {
                wcscat_s(szBuffer, L"CSSL certificate date that was received from the server is bad.The certificate is expired.");
            }
            if (*(DWORD*)lpvStatusInformation & WINHTTP_CALLBACK_STATUS_FLAG_SECURITY_CHANNEL_ERROR)  //80000000
            {
                wcscat_s(szBuffer, L"The application experienced an internal error loading the SSL libraries.");
            }
        }
        else
        {
            swprintf(szBuffer, sizeof(szBuffer), L"SECURE_FAILURE (%d)",  dwStatusInformationLength);
        }
        break;

    case WINHTTP_CALLBACK_STATUS_SENDING_REQUEST:
        // Sending the information request to the server.The lpvStatusInformation parameter is NULL.
        swprintf(szBuffer, sizeof(szBuffer), L"SENDING_REQUEST (%d)",  dwStatusInformationLength);
        break;

    case WINHTTP_CALLBACK_STATUS_SENDREQUEST_COMPLETE:
            swprintf(szBuffer, sizeof(szBuffer), L"SENDREQUEST_COMPLETE (%d)",   dwStatusInformationLength);

            // Prepare the request handle to receive a response.
            if (WinHttpReceiveResponse( cpContext->hRequest, NULL) == FALSE)
            {
                Cleanup(cpContext);
            }
            break;

    case WINHTTP_CALLBACK_STATUS_WRITE_COMPLETE:
        //Data was successfully written to the server. The lpvStatusInformation parameter contains a pointer to a DWORD that indicates the number of bytes written.
        //When used by WinHttpWebSocketSend, the lpvStatusInformation parameter contains a pointer to a WINHTTP_WEB_SOCKET_STATUS structure,
        //and the dwStatusInformationLength parameter indicates the size of lpvStatusInformation.
        if (lpvStatusInformation)
        {
            swprintf(szBuffer, sizeof(szBuffer), L"WRITE_COMPLETE (%d)",  *(DWORD*)lpvStatusInformation);
        }
        else
        {
            swprintf(szBuffer, sizeof(szBuffer), L"WRITE_COMPLETE (%d)",  dwStatusInformationLength);
        }
        break;

    case WINHTTP_CALLBACK_STATUS_GETPROXYFORURL_COMPLETE:
        // The operation initiated by a call to WinHttpGetProxyForUrlEx is complete. Data is available to be retrieved with WinHttpReadData.
        swprintf(szBuffer, sizeof(szBuffer), L"GETPROXYFORURL_COMPLETE (%d)",  dwStatusInformationLength);
        break;

    case WINHTTP_CALLBACK_STATUS_CLOSE_COMPLETE:
        // The connection was successfully closed via a call to WinHttpWebSocketClose.
        swprintf(szBuffer, sizeof(szBuffer), L"CLOSE_COMPLETE (%d)",  dwStatusInformationLength);
        break;

    case WINHTTP_CALLBACK_STATUS_SHUTDOWN_COMPLETE:
        // The connection was successfully shut down via a call to WinHttpWebSocketShutdown
        swprintf(szBuffer, sizeof(szBuffer), L"SHUTDOWN_COMPLETE (%d)",  dwStatusInformationLength);
        break;

    default:
            swprintf(szBuffer, sizeof(szBuffer),L"Unknown/unhandled callback - status %d given", dwInternetStatus);
            break;
    }

    printf("%wsn",szBuffer);
    // Add the callback information to the listbox.
    //LRESULT index = SendDlgItemMessage( cpContext->hWindow, IDC_CBLIST, LB_ADDSTRING, 0, (LPARAM)szBuffer);
    //SendDlgItemMessage(cpContext->hWindow, IDC_CBLIST, LB_SETTOPINDEX, index, 0);

}

int main()
{
    #define ZC L"http://127.0.0.1:40450"

    for (int i = 0; i < 2000; i++)
    {
   
        // Create the session handle using the default settings.
        HANDLE hSession = WinHttpOpen( L"Asynchronous WinHTTP Demo",
                                WINHTTP_ACCESS_TYPE_DEFAULT_PROXY,
                                WINHTTP_NO_PROXY_NAME,
                                WINHTTP_NO_PROXY_BYPASS,
                                WINHTTP_FLAG_ASYNC);

        // Check to see if the session handle was successfully created.
        if(hSession != NULL)
        {          
            REQUEST_CONTEXT* rcContext = new REQUEST_CONTEXT;
            if (rcContext)
            {
                memset(rcContext,0,sizeof(REQUEST_CONTEXT));
                rcContext->URL = new wchar_t[256];
               
                rcContext->ReceiveTimeout = 5000;
                rcContext->ConnectTimeout = 5000;
                rcContext->ResolveTimeout = 5000;
                rcContext->SendTimeout = 5000;
                rcContext->hSession = hSession;
                if (!rcContext->URL)
                {
                    delete rcContext;
                    WinHttpCloseHandle(hSession);
                    continue;
                }
                wcscpy(rcContext->URL,ZC);

                char* request = "<?xml version="1.0" encoding="windows-1251"?>"
                    "<soapenv:Envelope xmlns:env="http://schemas.xmlsoap.org/soap/envelope">"
                    "<soapenv:Header/>"
                    "<soapenv:Body/>"                  
                    "</soapenv:Envelope>";

                rcContext->SendBuffer = NULL;

                int f = strlen(request);

                rcContext->SendBuffer = new char[f+1];
                if (rcContext->SendBuffer)
                {
                    memset(rcContext->SendBuffer,0,f+1);
                    strncpy(rcContext->SendBuffer,request,f);
                }
                BOOL fRequest = SendRequest(rcContext);
//Sleep(1);
            }          
        }
    }
   
    getchar();
    printf("CounterGood = %d, CounterBad = %dn",CounterGood,CounterBad);   
    Sleep(2000);
    return 0;
}

Richard MacCutchan13-Sep-19 1:16

Richard MacCutchan

13-Sep-19 1:16

You cannot expect anyone to plough through those 900 or so lines of code on your behalf. Please remove all the code not related to your problem and explain what the problem is, in proper detail.

Victor Nijegorodov13-Sep-19 2:26

Victor Nijegorodov

13-Sep-19 2:26

Diprom wrote:
After cyclic sending of n-requests, error 12029 is often generated.

What API call causes this error?

Diprom13-Sep-19 2:30

Diprom

13-Sep-19 2:30

SendRequest(rcContext);
Although this call always terminates normally. 12029 I catch in the callback AsyncCallback

Victor Nijegorodov13-Sep-19 2:38

Victor Nijegorodov

13-Sep-19 2:38

SendRequest looks like your own function. It calls a lot of WinHTTP functions. So which one of these WinHTTP functions fails with this error?

Visual Studio 2017 C++ Static analyzer (or in ReSharper C++)

Randor 14-Sep-19 3:03

Randor

14-Sep-19 3:03

Hi,

Diprom wrote:
After cyclic sending of n-requests, error 12029 is often generated.

The Windows operating system limits the number of half-open TCP connections. On the Windows 10 operating system you will be limited to 20 and on the older operating systems it could be as low as 10.

Diprom wrote:
for (int i = 0; i < 2000; i++)

That's alot of asynchronous connections... the Windows operating system will not allow you to make 2000 outgoing connections this fast.

Best Wishes,
-David Delaune

Scientiæ de conservata veritate.

Maximilien12-Sep-19 4:21

Maximilien

12-Sep-19 4:21

Is there a switch in Visual Studio C++ Static Analyzer to catch the uninitialized member i.

Or if you are using ReSharper C++ which one of the gazillion inspection options I would need to check to catch this?

Thanks.

C++

class Test
{
public:
    Test(int i) : m_i(i)
    {
        std::cout << m_i << std::endl;
    };
    int m_i;
};

class MainTest
{
public:
    MainTest() : m_Test(i)  {}; // i is not initialized here... 

    Test m_Test; 
    int i = 33; // if I put this line before the line above it will be corrected.
};

int main()
{
    MainTest m;

    std::cout << "Hello World!\n"; 
}

I'd rather be phishing!

Re: Visual Studio 2017 C++ Static analyzer (or in ReSharper C++)

Stefan_Lang12-Sep-19 5:33

Re: Visual Studio 2017 C++ Static analyzer (or in ReSharper C++)

12-Sep-19 5:33

Can't help you there, I would have expected VS to issue a warning. D'Oh! | :doh:

That said, it shouldn't make a difference where you put the declaration (and initialization) of i, because section 12.6.2 of the C++ standard says the order of initialization is always:

1. virtual base classes
2. base classes
3. non-static members
(4. the body of the constructor is executed)

Therefore, i can never be initialized by the time the base constructor is called (and if it is, the compiler has an error).

The only way I can think of to initialize i before the base class, is having a (potentially different) base class initialize it - either by moving the member variable into that base class, or with the help of CRTP

C++

template <typename T>
struct make_i_great_again {
    make_i_great_again(T& t) { t.i = 33; }
};
class Test {
...
};
class MainTest : public make_i_great_again<MainTest>, Test
{
public:
    MainTest() : make_i_great_again(*this), Test(i) {}
    int i;
};

Technically this is a hack, because by the time you pass *this to your base class, this isn't properly constructed. But since you're not reading fromo it, it might actually work.

P.S.: oh well, forget all of the above. Somehow I thought you were inheriting from Test ....

Anyway, you could simply use a static const instead of using your member variable:

C++

class MainTest {
    static const int I_INIT = 33;
public:
    MainTest() : m_Test(I_INIT) {}
    Test m_Test;
    int i = I_INIT;
};

CPallini12-Sep-19 21:08

CPallini

12-Sep-19 21:08

Now that is pretty interesting.
The following code

C++

#include <iostream>
using namespace std;
class Foo
{
  int a = b;
  int b = 5;

public:
  void show(){ cout << "a " << a << ", b " << b << endl;}

};

class Boo
{
  int a;
  int b;
public:
  Boo(): a(b), b(5){}
  void show(){ cout << "a " << a << ", b " << b << endl;}
};


class Goo
{
  int a;
  int b=5;
public:
  Goo():a(b){}
  void show(){ cout << "a " << a << ", b " << b << endl;}
};


int main()
{
  Foo f;
  f.show();
  Boo b;
  b.show();
  Goo g;
  g.show();
}

compiled with

g++ -Wall

issues NO warning and produces the following output on my Linux box

a 0, b 5
a 0, b 5
a 32766, b 5

The lesson I learnt (while waiting for more clever people to add insight) is "Timeo Danaos and C++ Default Initializers for class members".

Re: Visual Studio 2017 C++ Static analyzer (or in ReSharper C++)

Stefan_Lang12-Sep-19 22:19

Re: Visual Studio 2017 C++ Static analyzer (or in ReSharper C++)

12-Sep-19 22:19

I've tried online GDB because I don't trust VS to be 100% standards comform, and it does the same. (not sure how to set warning level though; but it's gcc, so I wouldn't expect a different result than you). Then I looked up order of initialization, and although there are pretty detailed descriptions on the order of initializations of the stuff mentioned in a constructor, I haven't found a hint on when a static initialization is taking place!

Btw.: interesting choice of names! You forgot Loo, though Wink | ;-)

P.S.:
While online GDB also does not offer a warning, it does generate a different result when run:
a 0, b 5
a 32764, b 5
a 0, b 5

I'm not sure what to make of this Confused | :confused:

P.P.S.: link to onlinegdb:
https://www.onlinegdb.com/online_c++_compiler[^]

modified 13-Sep-19 4:24am.

Stefan_Lang12-Sep-19 23:26

Re: Visual Studio 2017 C++ Static analyzer (or in ReSharper C++)

12-Sep-19 23:26

Ok, I'll add some more mystery. Here's my take:

C++

#include <iostream>
using namespace std;
class Loo
{
public:
    static int x;
    static int y;
    static int z;
    int a;
    int b = ++y;
    int c;
    Loo() : a(++x), c(b+(++z)) {}
    Loo(int i) : a(++b), b(++i), c(++b) {}
    void show(){ cout << "a " << a << ", b " << b << ", c " << c << endl;}
    static void show_(){ cout << "x " << x << ", y " << y << ", z " << z << endl;}
};
int Loo::x = 0;
int Loo::y = 0;
int Loo::z = 0;
int main()
{
  Loo::show_();
  Loo l;
  l.show();
  Loo::show_();
  Loo l5(5);
  l5.show();
  Loo::show_();
  return 0;
}

And the output I get is:

x 0, y 0, z 0                                                                                          
a 1, b 1, c 2                                                                                          
x 1, y 1, z 1                                                                                          
a 1, b 7, c 7                                                                                          
x 1, y 1, z 1

The first two lines are unspectactular: they show what can be expected from the code.

The third line is also unsurprising. Importantly, it shows that the member initialization of b was invoked by the default constructor (y=1).

The fourth line however is very odd: It starts with a=1. How? Let's take apart the commonly known rules on initilization order: the initializer list gets processed left to right for all virtual base classes, than all base classes, then all members. We only have members, so initialization order is a, then b, then c.

Next, according to this site Non-static data members - cppreference.com[^] the non-static member initialization of b gets skipped, because b is on the initalizer list. This means, b is not initialized at all by the time a is getting initialized! Note that y remains unchanged, proving that the member initializer is not invoked! Therefore the value assigned to a is undefined. As it seems, in this case b assumes a value of 0, incremented to 1, and then assigned to a.

Next, b gets initialized. It's value is based on i, which is 5, so the value of b should be 6. The output shows 7 - but let's look further: we still have to initialize c, which again is based b, incrementing it. Therefore b is now 7, and c too.

Ok, all is well, except that the value of a is undefined, even though b appears to be initialized in two places! Only that one initialization is skipped because of the other that is happening too late Dead | X|

Stefan_Lang12-Sep-19 22:46