C / C++ / MFC

Re: How to do Automation in MFC for Microsoft Access?

19-Oct-06 5:17

sujeet_kulk wrote:
...name the classes and methods involved...

They are in the .h and .cpp files that were added to your project. The first one you'll need is _Application. Call its CreateDispatch() method.

"Approved Workmen Are Not Ashamed" - 2 Timothy 2:15

"Judge not by the eye but by the heart." - Native American Proverb

sujeet_kulk19-Oct-06 5:29

sujeet_kulk

19-Oct-06 5:29

Fine with that but how to get the rows and columns of a datatable, I mean which are the classes.

Re: How to do Automation in MFC for Microsoft Access?

David Crow19-Oct-06 7:49

How to set default settings for video compression dialog box

19-Oct-06 7:49

sujeet_kulk wrote:
...which are the classes.

Have you looked at AccessObject?

"Approved Workmen Are Not Ashamed" - 2 Timothy 2:15

"Judge not by the eye but by the heart." - Native American Proverb

Hemant kulkarni18-Oct-06 21:03

Hemant kulkarni

18-Oct-06 21:03

Hi,

I want to compress the video data using XviD codec. How I can set this codec as default codec for compression in "AVISaveOptions" API which displays a dialog box to user. I don't want to show that dialog box but instead it should use the default codec from. How can set the default codec value?

Regards,
Hemant.

how to optimize IF condition

xcavin18-Oct-06 21:04

xcavin

18-Oct-06 21:04

I have following line of code:

if(a==Z||<br />
b==Z||<br />
c==Z||<br />
d==Z||<br />
e==Z||<br />
f==Z||<br />
g==Z)<br />
{<br />
.<br />
.<br />
.<br />
}

can this be written in a better way ?

p.s all the variables are of type enums

Re: how to optimize IF condition

David Crow19-Oct-06 4:22

Re: how to optimize IF condition

19-Oct-06 4:22

How about:

if (a <= Z && Z <= g)
   ...

Of course, trying to one-up the optimizer is usually a lost cause.

"Approved Workmen Are Not Ashamed" - 2 Timothy 2:15

"Judge not by the eye but by the heart." - Native American Proverb

Zac Howland19-Oct-06 5:04

Zac Howland

19-Oct-06 5:04

Is Z a enumeration value or a variable? If they are all variables, you really can't do much without making assumptions about ordering for the values.

If you decide to become a software engineer, you are signing up to have a 1/2" piece of silicon tell you exactly how stupid you really are for 8 hours a day, 5 days a week

Zac

Help

Anamika200518-Oct-06 20:21

Anamika2005

18-Oct-06 20:21

Can Somebody help me..
i have one ListBox and one combobox . i want that when user select any item in the ListBox , the path of that item is got selected in the combobox..

How to achieve this..
Please help me in this..

Thanks and Regards

Re: Help

Archyami18-Oct-06 20:34

18-Oct-06 20:34

step1:
In the ui designer, right click the control (combobox) and
click 'wizard'.
You can add an event to it.
Then, an event function will be created in the classes you chose.

step2:
Add code in the event function.
Something like this->GetDlgText(...)

Re: Help

Hamid_RT18-Oct-06 20:45

Hamid_RT

18-Oct-06 20:45

You need to insert this item to ComboBox withAddStringand use of

<br />
SetCurlSel

WhiteSky

Re: Help

David Crow19-Oct-06 4:24

19-Oct-06 4:24

Shikha Jain wrote:
How to achieve this..

Are you handling the LBN_SELCHANGE notification?

"Approved Workmen Are Not Ashamed" - 2 Timothy 2:15

"Judge not by the eye but by the heart." - Native American Proverb

TCP receive 2

Archyami18-Oct-06 18:39

18-Oct-06 18:39

this is an continuous message...

Below is the client code to receive 2 replies from a server:

/*********/

BOOL streamclient(char* ip, unsigned short port, char* message, AString* astr_reply)
{
//
// Create a TCP/IP stream socket
//
SOCKET theSocket;

theSocket=socket(AF_INET,SOCK_STREAM,IPPROTO_TCP);
if(theSocket==INVALID_SOCKET)
{
eprintf("ServerHandler:streamclient()\nsocket() %s %u", ip, port);
return FALSE;
}

//
// Fill in the address structure
//
SOCKADDR_IN saServer;
DWORD dwIPAddr=inet_addr(ip);

saServer.sin_family=AF_INET;
saServer.sin_addr.s_addr=*((u_long FAR*)((char*)&dwIPAddr));
saServer.sin_port=htons(port);

//
// connect to the server
//
int nRet;

nRet=connect(theSocket, // Socket
(LPSOCKADDR)&saServer, // Server address
sizeof(struct sockaddr));// Length of server address structure
if(nRet==SOCKET_ERROR)
{
closesocket(theSocket);
eprintf("ServerHandler:streamclient()\nconnect() %s %u", ip, port);
return FALSE;
}

//
// Send data to the server
//
nRet=send(theSocket, // Connected socket
message, // Data buffer
(int)strlen(message), // Length of data
0); // Flags
if(nRet==SOCKET_ERROR)
{
closesocket(theSocket);
eprintf("ServerHandler:streamclient()\nsend() %s %u", ip, port);
return FALSE;
}
aprintf("sent to CATOS (%s %u):\n%s", ip, port, message);

//
// Wait for a reply
//
char* szBuf;
AString astr;

/* receive ACK */
szBuf=(char*)malloc(sizeof(char)*(CATOS_BUFFER_SIZE+1));
if(szBuf==NULL)
{
eprintf("ServerHandler:streamclient()\nszBuf==NULL");
return FALSE;
}

nRet=recv(theSocket, // Connected socket
szBuf, // Receive buffer
CATOS_BUFFER_SIZE,//sizeof(szBuf), // Size of receive buffer
0); // Flags
if(nRet==SOCKET_ERROR)
{
closesocket(theSocket);
free(szBuf);
eprintf("ServerHandler:streamclient()\nrecv() %s %u", ip, port);
return FALSE;
}
if(astr.Set(szBuf))
aprintf("received from server:\n%s", astr.SubString(0, ETX, TRUE));
else
aprintf("received from server:\n[ACK]");

/* receive useful reply */
// clear szBuf and wait for a while so that recv() becomes ready:
for(int i=0; i<catos_buffer_size; i++)
="" szbuf[i]="\0" ;
="" sleep(second_receive_delay);
="" nret="recv(theSocket," connected="" socket
="" szbuf,="" receive="" buffer
="" catos_buffer_size,="" sizeof(szbuf),="" size="" of="" 0);="" flags
="" if(nret="=SOCKET_ERROR)
" {
="" closesocket(thesocket);
="" free(szbuf);
="" eprintf("serverhandler:streamclient()\nrecv()="" %s="" %u",="" ip,="" port);
="" aprintf("serverhandler:streamclient()\nrecv()="" port);return="" false;
="" }

="" if(astr_reply-="">Set(szBuf, nRet))
{
//
// Display the received data
//
free(szBuf);
closesocket(theSocket);
aprintf("received from server:\n%s", astr_reply->Value);
/* exception */
return TRUE;
}
aprintf("received from server:\n[useful reply]");
free(szBuf);
closesocket(theSocket);
return FALSE;
}

BOOL ServerHandler::Send(char* ip, unsigned short port, char* message)
{
WORD wVersionRequested;
WSADATA wsaData;
int nRet;
int i;

wVersionRequested=MAKEWORD(1,1);
nRet=WSAStartup(wVersionRequested, &wsaData);

if(wsaData.wVersion==wVersionRequested)
{
for(i=0; i

mpk197918-Oct-06 20:34

mpk1979

18-Oct-06 20:34

hi,
is it showing exception which executing aprintf statement or after returning from aprintf statement

mpk1979

Archyami18-Oct-06 20:43

18-Oct-06 20:43

If a printf("aprintf OK"); is added after calling aprintf,
the message "aprintf OK" can be shown.
then goes to return TRUE;

But printf("returned") if added in the lower function, it does not show "returned".

So, I think something causes the exception for exiting the upper function.

Please advise.

Mark Salsbery19-Oct-06 5:51

Mark Salsbery

19-Oct-06 5:51

I'm not sure what the server is sending you, but you send this many bytes

(int)strlen(message), // Length of data

to the server (you're not sending the NULL terminator at the end of the message).

On the first receive from the server you assume the string is NULL terminated

if(astr.Set(szBuf))

Try either sending "strlen(message) + 1" bytes or using "if(astr.Set(szBuf,nRet))" instead of
"if(astr.Set(szBuf))".

Mark

Archyami19-Oct-06 15:35

Re: TCP receive 2 [modified]

19-Oct-06 15:35

Thanks Mark!

I tried to send "strlen(message) + 1" bytes to the server.
The exception appears less often, but still occurs.

The exception message is:
"DAMAGE: after Normal block (#1409) at 0x0032EF20"

I cannot use 'try' to catch it. Using debug mode fails to locate the error line...

Please help me again.
It should be very close to the solution.
Thanks!

Mark Salsbery19-Oct-06 16:26

Mark Salsbery

19-Oct-06 16:26

Archyami wrote:
I tried to send "strlen(message) + 1" bytes to the server.
The exception appears less often, but still occurs

That's fine. You need to do the same on your sends FROM the server as well otherwise this line
is going to be problematic on the client side:

if(astr.Set(szBuf))

You are still assuming that szBuf has a NULL terminator. Whether or not this is causing the
exception I don't know.

A few notes and questions...

You allocate a receive buffer CATOS_BUFFER_SIZE+1 bytes in length but only recv CATOS_BUFFER_SIZE
bytes into it. Why?

I believe you mentioned using blocking sockets in another post. If so, the Sleep() call is
useless since the second recv call will block until you receive some more bytes or the
socket closes or error occurs. It looks like you're waiting until "for sure" all the bytes have
arrived before trying the second receive. This may work for a few "packets" but is very
inefficient for a tcp socket. Instead, it works better to keep calling recv until you get the
bytes you are expecting (remember, recv() won't always give them all to you in one call). To
receive CATOS_BUFFER_SIZE bytes try something like:

szBuf=(char*)malloc(sizeof(char)*(CATOS_BUFFER_SIZE+1));

int TotalBytesReceived = 0;

while (TotalBytesReceived < CATOS_BUFFER_SIZE)
{
	int CurBytesReceived = ::recv(theSocket, &szBuf[TotalBytesReceived], CATOS_BUFFER_SIZE - TotalBytesReceived, 0);
	if (CurBytesReceived == 0)
	{
		// connection gracefully closed!!
		break;
	}
	else if (CurBytesReceived == SOCKET_ERROR)
	{
		int rc = WSAGetLastError();
		if (rc != WSAEWOULDBLOCK)
		{
			break;  // socket error occurred!!
		}
	}
	else
	{
		TotalBytesReceived += CurBytesReceived;
	}
}

if (TotalBytesReceived == CATOS_BUFFER_SIZE)
{
	// Successfully received CATOS_BUFFER_SIZE bytes
	//do something with szBuf
}
else
{
	// something happened before we received CATOS_BUFFER_SIZE bytes
}

Make sure you send EXACTLY CATOS_BUFFER_SIZE from the server...if you don't you'll be stuck in
the loop waiting Smile | :)

If you can't always send the right amount you could timeout or something.

Mark

EDIT: By the way, you shouldn't ever get a WSAEWOULDBLOCK error on a blocking socket.
I added the check for WSAEWOULDBLOCK as an example of using a non-blocking socket.

More EDITS: Bad grammer, spelling, attitude, etc.

-- modified at 22:32 Thursday 19th October, 2006

Archyami20-Oct-06 6:00

20-Oct-06 6:00

I modified the server "send" with data length +1.
The exception does not occur.
Thanks very much, Mark!

I have a few questions:
1. The message eg. equals "abc". Its length is 3.
Why should I send its length as 4?
(The server is checked to send data within the length of CATOS_BUFFER_SIZE.)

2. The recv buffer is allocated with 1 more byte for safe (may be it is a risk...)
My design is that if CATOS_BUFFER_SIZE==10 and message comes from the server as "1234567890", it can hold the message. Indeed, a terminator is at the end (here is '0'). If '\0' is padded by the server, it can still hold the message.
'\0' is padded automatically for initializing an char array.
Please advise if my analysis is wrong.

3. If the server is checked to send data within the length of CATOS_BUFFER_SIZE, is it possible that the client recv() may receive the message sereral times instead of once?
I mean: recv() holds the application (thread). 'several times' refers to 1 recv() receives a part of the message, several recv() receives all message 'packages'.

Please advise. Smile | :)