C / C++ / MFC

12-Sep-05 23:59

Hello..

I'm a beginner with Visual C++.. (have only done very very basic C++ programming).. I'm trying to communicate with a microcontroller using serial communication.. I tried to do it from scratch using the Windows functions..this is what my code looks like..

 #include "stdafx.h"<br />
<br />
int _tmain()<br />
{<br />
<br />
HANDLE h =	CreateFile("COM3", GENERIC_READ|GENERIC_WRITE, 0, 0, OPEN_EXISTING, 0, 0);<br />
	if (h == 0)<br />
	{<br />
		printf("Can't open com port (1)\n");<br />
		return 1;<br />
	}<br />
	DCB dcb;<br />
	memset(&dcb, 0, sizeof(DCB));<br />
	dcb.DCBlength = sizeof(DCB);<br />
	dcb.BaudRate = 19200;<br />
	dcb.fBinary = TRUE;<br />
	dcb.fParity = FALSE;<br />
	dcb.ByteSize = 8;<br />
	dcb.Parity = NOPARITY;<br />
	dcb.StopBits = ONESTOPBIT;<br />
	BOOL result = SetCommState(h, &dcb);<br />
	if (!result)<br />
	{<br />
		printf("Can't set com port state(2)\n");<br />
		return 1;<br />
	}<br />
<br />
	if (result)<br />
		printf("Have Set com port state\n");<br />
<br />
	char buffer[100];<br />
	DWORD bytesRead = 0;<br />
	while (true)<br />
	{<br />
		printf("In while\n"); <br />
			<br />
		memset(buffer, 0, sizeof(buffer));<br />
		if (ReadFile(h, buffer, sizeof(buffer)-1, &bytesRead, 0))<br />
		{<br />
			printf("Read file has a result\n"); <br />
			if (bytesRead != 0)<br />
			{<br />
				printf("Got some bytes\n"); <br />
				printf ("%s", buffer);<br />
			}<br />
			<br />
			else {<br />
				printf("No bytes read\n"); <br />
			}<br />
		}<br />
<br />
		else {<br />
			printf("Readfile didnt give proper result \n"); 	<br />
		}<br />
		Sleep(200);<br />
	}<br />
<br />
	// Close session<br />
	CloseHandle(h);<br />
<br />
	return 0;

he micro is continously sending characters to the serial port.. when i run the program.. the port does gets initialized properly (debug statement printed ) then some characters are recieved but they are unintelligble.. i've checked the speed and all other settings for the com port and they are the same as the micro and the micro's usart is working fine.. can anyone see why i'm getting garbage..

Thank you for the help..

MailtoGops13-Sep-05 3:15

MailtoGops

13-Sep-05 3:15

Hi,

Can you check this with Hyperterminal tool provided along with the operating systems?. If hyperterminal prints the right characters send by the microcontroller then we can dig into your code... Could you please do this??

And also check whether the characters sent by the microcontroller are ascii or unicode complaint..

" Action without vision is only passing time,
Vision without action is merely day dreaming,
But vision with action can change the world "

- Words from Nelson Mandela

Thanks & Regards,

Gopalakrishnan

Aditi48413-Sep-05 3:50

13-Sep-05 3:50

Hello..

Thanks for your reply.. I've checked with Hyper Terminal.. the characters are receieved properly.. the micro is sending ASCII characters..

Regards,
Aditi

John R. Shaw13-Sep-05 4:06

John R. Shaw

13-Sep-05 4:06

We need more beginners like you. You have good instincts as to how to figure out what the problem is. (You also have the option of using the TRACE() marcos, as well as printf(), in order to print debugging resutls).

Unfortunaley your code is good enough that it should probably be working. It does need improvement, but that's not the problem. What the problem is I do not know and I've written severial serial communications programs. In otherwords, I'd have to be degugging it.

SOME COMMENTS:
1) CreateFile() doesn't return 0 on failure, it returns INVALID_HANDLE_VALUE (which is equal to -1). All this tells us it that even thou your code does not know if it failed to open a port, it has succeded because you are receiving data. (Oh, if it did fail you code would report that it fail to open port 1 not 3).
2) Use: if(result) {...} else {...}. Not: if(result) {...} if(!resutl) {...}
3) If ReadFile() succededs then bytesRead should not be 0, so checking for it makes no since.

GARBAGE IS A RELITIVE TERM:
1) Your code implies that you are expecting to receive (ASCII) text. If that is not what the microcontroller is returning, then it will look like garbage.
2) What are you expecting to receive from the microcontroller?

FYI:
I assume you know that you are writting C code and not C++ code.
(It has no effect on your problem or its solution).

INTP
"The more help VB provides VB programmers, the more miserable your life as a C++ programmer becomes."
Andrew W. Troelsen

Roger Stoltz13-Sep-05 6:35

Roger Stoltz

13-Sep-05 6:35

There are two things at the top of my head: flow control and timeouts.
In most cases when you are beginning to communicate with a MC or similar you don't need any flow control and you would select "None" in Hyperterminal.
In your code this would mean the following setting that you have omitted:

<br />
dcb.fDtrControl = DTR_CONTROL_ENABLE;<br />
dcb.fRtsControl = RTS_CONTROL_ENABLE;<br />

Since you have fillled the DCB struct with zeros, the HW signals DataTerminalReady and RequestToSend will be inactive. Depending on connected hardware this could have various results from no communication to no impact at all.

Regarding timeouts you may want to read about it in MSDN under the documentation for the ::SetCommTimeouts function.

Tip of the day: use PortMon!
I have found PortMon to be extremely helpful in situations like the one you are describing. PortMon is freeware and can be downloaded at http://www.sysinternals.com/utilities/portmon.html[^]
With PortMon it's easy to determine how the port is setup and see what is sent and received in either hex or ASCII.
Make sure that the setup sequence looks the same for both your app and HT since HT seems to be working.

Hope this helps
--
Roger

Aditi48413-Sep-05 23:26

13-Sep-05 23:26

Hello all..

Thank you for the replies.. Right now i'm sitting with the problem that the program on the PC is SOMETIMES getting the expected data from the micro but sometimes it gets the unintelligble characters.. I've noticed that for instance if i run the program and its gets garbage.. then i close it and wait a bit,run it a coupla times and then it gets the right stuff once.. then if i run it again it'll give garbage again.. and for the next coupla times it'll just give garbage.. then after a coupla tries it'll give the right stuff after some time ??!!!

In my code.. I use CloseHandle() to close the serial connection.. but i've noticed that after running the program and exiting it and then using the a terminal program such as HyperTerminal.. then HyperTerminal has trouble getting the characters from the serial port.. but after giving some time then HyperTerminal starts getting the characters properly..

The program always garbage when the micro starts sending characters to it (at power up).. and then has to be run a coupla times before it'll give the right output once..

Is there any other method to close the serial connection properly ?

I know my description above is not very technical but I'm a beginner and am trying to give as much info as I can make sense of in this program..

Thank you for your help..

Aditi

P.S. I did put in the DTR and RTS control ENABLE lines in the code as suggested by Roger.. but it still behaves the same way..

Roger Stoltz14-Sep-05 1:00

Roger Stoltz

14-Sep-05 1:00

Have you compared the setup sequences for your app and HyperTerminal with PortMon?
Any diffs?

Aditi484 wrote:
In my code.. I use CloseHandle() to close the serial connection..

::CloseHandle() is the proper call to make.
If you are referring to the code you posted in your first mail you'll never reach ::CloseHandle() since it's outside the while-loop. This should make HT complain about the port being busy.
How do you exit your application? Terminating it with <shift+f5>?

Is it a real RS232 connection you're using or is it some simulated serial connection over USB?

It might be helpful if you could log the setup sequence with PortMon and cut it out and send it in your next post.

--
Roger

Aditi48414-Sep-05 1:36

14-Sep-05 1:36

Hello..

I just used PortMon and the setup is right between the app and hyperterminal.. I'm using a normal serial port...

Below is the log of what PortMmon recorded..

 4	0.00006984	comm console.ex	IRP_MJ_CREATE	Serial1	SUCCESS	Options: Open 	<br />
5	0.00000559	comm console.ex	IOCTL_SERIAL_GET_BAUD_RATE	Serial1	SUCCESS		<br />
6	0.00000196	comm console.ex	IOCTL_SERIAL_GET_LINE_CONTROL	Serial1	SUCCESS		<br />
7	0.00000196	comm console.ex	IOCTL_SERIAL_GET_CHARS	Serial1	SUCCESS		<br />
8	0.00000168	comm console.ex	IOCTL_SERIAL_GET_HANDFLOW	Serial1	SUCCESS		<br />
9	0.00000950	comm console.ex	IOCTL_SERIAL_SET_BAUD_RATE	Serial1	SUCCESS	Rate: 19200	<br />
10	0.00000587	comm console.ex	IOCTL_SERIAL_SET_RTS	Serial1	SUCCESS		<br />
11	0.00000559	comm console.ex	IOCTL_SERIAL_SET_DTR	Serial1	SUCCESS		<br />
12	0.00000531	comm console.ex	IOCTL_SERIAL_SET_LINE_CONTROL	Serial1	SUCCESS	StopBits: 1 Parity: NONE WordLength: 8	<br />
13	0.00000391	comm console.ex	IOCTL_SERIAL_SET_CHAR	Serial1	SUCCESS	EOF:0 ERR:0 BRK:0 EVT:0 XON:0 XOFF:0	<br />
14	0.00000531	comm console.ex	IOCTL_SERIAL_SET_HANDFLOW	Serial1	SUCCESS	Shake:1 Replace:40 XonLimit:0 XoffLimit:0	<br />
15	0.00819546	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
16	0.00986215	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
17	0.00978951	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
18	0.00971129	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
19	0.00959787	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
20	0.00904864	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
21	0.00977275	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
22	0.00979733	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
23	0.00865725	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
24	0.00866004	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
25	0.00002375	comm console.ex	IRP_MJ_READ	Serial1	SUCCESS	Length 99: .*W...............M.................M.................M.........	<br />
26	0.00002375	comm console.ex	IRP_MJ_READ	Serial1	SUCCESS	Length 99: .........M.................M.................M.................M	<br />
27	0.00002319	comm console.ex	IRP_MJ_READ	Serial1	SUCCESS	Length 99: M.................M.................M.................M.........	<br />
28	0.00002347	comm console.ex	IRP_MJ_READ	Serial1	SUCCESS	Length 99: .........M.................M.................M.................M	<br />
29	0.00002570	comm console.ex	IRP_MJ_READ	Serial1	SUCCESS	Length 99: M.................M.................M.................M.........	<br />
30	0.00002542	comm console.ex	IRP_MJ_READ	Serial1	SUCCESS	Length 99: .........M.................M.................M.................M	<br />
31	0.00002738	comm console.ex	IRP_MJ_READ	Serial1	SUCCESS	Length 99: M.................M.................M.................M.........	<br />
32	0.00002570	comm console.ex	IRP_MJ_READ	Serial1	SUCCESS	Length 99: .........M.................M.................M.................M	<br />
33	0.00002514	comm console.ex	IRP_MJ_READ	Serial1	SUCCESS	Length 99: M.................M.................M.................M.........	<br />
34	0.00002514	comm console.ex	IRP_MJ_READ	Serial1	SUCCESS	Length 99: .........M.................M.................M.................M	<br />
35	0.00002598	comm console.ex	IRP_MJ_READ	Serial1	SUCCESS	Length 99: M.................M.................M.................M.........	<br />
36	0.00002514	comm console.ex	IRP_MJ_READ	Serial1	SUCCESS	Length 99: .........M.................M.................M.................M	<br />
37	0.00002570	comm console.ex	IRP_MJ_READ	Serial1	SUCCESS	Length 99: M.................M.................M.................M.........	<br />
38	0.00002570	comm console.ex	IRP_MJ_READ	Serial1	SUCCESS	Length 99: .........M.................M.................M.................M	<br />
39	0.00002542	comm console.ex	IRP_MJ_READ	Serial1	SUCCESS	Length 99: M.................M.................M.................M.........	<br />
40	0.00002542	comm console.ex	IRP_MJ_READ	Serial1	SUCCESS	Length 99: .........M.................M.................M.................M	<br />
41	0.00002486	comm console.ex	IRP_MJ_READ	Serial1	SUCCESS	Length 99: M.................M.................M.................M.........	<br />
42	0.00002514	comm console.ex	IRP_MJ_READ	Serial1	SUCCESS	Length 99: .........M.................M.................M.................M	<br />
43	0.00864188	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 19: M..................	<br />
44	0.00865976	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
45	0.00874022	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
46	0.00863909	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
47	0.00868714	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
48	0.00865026	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
49	0.00717968	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
50	0.00863601	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
51	0.00867764	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
52	0.00754062	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
53	0.00651982	comm console.ex	IRP_MJ_READ	Serial1	SUCCESS	Length 99: Start0087testokendStart0087testokendStart0087testokendStart0087t	<br />
54	0.00002123	comm console.ex	IRP_MJ_READ	Serial1	SUCCESS	Length 99: testokendStart0087testokendStart0087testokendStart0087testokendS	<br />
55	0.00002430	comm console.ex	IRP_MJ_READ	Serial1	SUCCESS	Length 99: Start0087testokendStart0087testokendStart0087testokendStart0087t	<br />
56	0.00002347	comm console.ex	IRP_MJ_READ	Serial1	SUCCESS	Length 99: testokendStart0087testokendStart0087testokendStart0087testokendS	<br />
57	0.00002375	comm console.ex	IRP_MJ_READ	Serial1	SUCCESS	Length 99: Start0087testokendStart0087testokendStart0087testokendStart0087t	<br />
58	0.00002375	comm console.ex	IRP_MJ_READ	Serial1	SUCCESS	Length 99: testokendStart0087testokendStart0087testokendStart0087testokendS	<br />
59	0.00002514	comm console.ex	IRP_MJ_READ	Serial1	SUCCESS	Length 99: Start0087testokendStart0087testokendStart0087testokendStart0087t	<br />
60	0.00002626	comm console.ex	IRP_MJ_READ	Serial1	SUCCESS	Length 99: testokendStart0087testokendStart0087testokendStart0087testokendS	<br />
61	0.00002626	comm console.ex	IRP_MJ_READ	Serial1	SUCCESS	Length 99: Start0087testokendStart0087testokendStart0087testokendStart0087t	<br />
62	0.00002430	comm console.ex	IRP_MJ_READ	Serial1	SUCCESS	Length 99: testokendStart0087testokendStart0087testokendStart0087testokendS	<br />
63	0.00002738	comm console.ex	IRP_MJ_READ	Serial1	SUCCESS	Length 99: Start0087testokendStart0087testokendStart0087testokendStart0087t	<br />
64	0.00002766	comm console.ex	IRP_MJ_READ	Serial1	SUCCESS	Length 99: testokendStart0087testokendStart0087testokendStart0087testokendS	<br />
65	0.00002570	comm console.ex	IRP_MJ_READ	Serial1	SUCCESS	Length 99: Start0087testokendStart0087testokendStart0087testokendStart0087t	<br />
66	0.00002766	comm console.ex	IRP_MJ_READ	Serial1	SUCCESS	Length 99: testokendStart0087testokendStart0087testokendStart0087testokendS	<br />
67	0.00002794	comm console.ex	IRP_MJ_READ	Serial1	SUCCESS	Length 99: Start0087testokendStart0087testokendStart0087testokendStart0087t	<br />
68	0.00002654	comm console.ex	IRP_MJ_READ	Serial1	SUCCESS	Length 99: testokendStart0087testokendStart0087testokendStart0087testokendS	<br />
69	0.00002011	comm console.ex	IRP_MJ_READ	Serial1	SUCCESS	Length 99: Start0087testokendStart0087testokendStart0087testokendStart0087t	<br />
70	0.00002570	comm console.ex	IRP_MJ_READ	Serial1	SUCCESS	Length 99: testokendStart0087testokendStart0087testokendStart0087testokendS	<br />
71	0.00772724	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 18: Start0087testokend	<br />
72	0.00842621	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
73	0.00828876	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
74	0.00910674	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
75	0.00837425	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
76	0.00890532	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
77	0.00913496	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
78	0.00783899	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
79	0.00822954	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
80	0.00905199	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
81	0.00778255	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
82	0.00891286	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
83	0.00916038	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
84	0.00911708	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
85	0.00827032	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
86	0.00898773	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
87	0.00820048	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
88	0.00804208	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
89	0.00910702	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
90	0.00791190	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
91	0.00912602	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
92	0.00838654	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
93	0.00910060	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
94	0.00817059	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
95	0.00912267	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
96	0.00824379	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
97	0.00907182	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
98	0.00775518	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
99	0.00858740	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
100	0.00827396	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
101	0.00947243	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
102	0.00836978	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
103	0.00934392	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
104	0.00875195	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
105	0.00858768	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
106	0.00968754	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
107	0.00972666	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
108	0.00970738	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
109	0.00913049	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
110	0.00973252	comm console.ex	IRP_MJ_READ	Serial1	TIMEOUT	Length 0: 	<br />
111	0.00000922	comm console.ex	IRP_MJ_CLEANUP	Serial1	SUCCESS		<br />
112	0.01114248	comm console.ex	IRP_MJ_CLOSE	Serial1	SUCCESS		<br />

Initially my micro was sending stuff continuously but now I'm just sending my test string a 100 times.. and then the micro doesnt send anything..

From this log what I can make out (please correct me if I'm wrong) that the serial port is setup correctly.. and then the program was waiting for some bytes and got nothing (the Length 0 part).. and then i switched on my micro..the micro sent the string 100 times, but the program got some characters which were garbage.. then the program was just looping through getting nothing (micro had finished sending the string 100 times) then i switched off-on the micro again and this time it recieved the right characters.. and then micro finishes sending the string so the program loops through getting nothing.. then i closed the console of the program.. and then PortMon gets "Cleanup and Close" messages which are successful..

Also I wanted to ask.. if after running my program.. to exit it I close the console window i run it from.. that effectievly ends the program and should result in Closehandle() being called (PortMon did get the "Cleanup and Close" messages ?? ) So then why after that does HyperTerminal still complain..

Thank you for your help..

Aditi

Roger Stoltz14-Sep-05 5:00

Roger Stoltz

14-Sep-05 5:00

The port seems to be setup good enough.
To put it in short terms: I suspect that your MC doesn't do what you think it does.

I tried running the code you've written and it works. It receives the bytes sent to the port and writes them to the console window.
Note that calling ::ReadFile in non-overlapped mode will be a blocking call. You decide for how long it should block and when to timeout and what for by a call to ::SetCommTimeouts after calling ::SetCommState.

Regarding ::CloseHandle() it cannot be called in the code you've written.
The call to ::CloseHandle() is on the other side of an endless loop.
Since you are running the app as a console app it is the responsability of the console to terminate the program running in the console, if it's possible, when you close the console window.
I suspect a call to _endthread() that will end your app and that would let the run-time system reclaim allocated resources such as the port since there is only one thread in your app. As a result of that you will see the cleanup and close statements in PortMon.

HyperTerminal might complain if the MC is malfunctioning or is not setup the same as HT, e.g. uses the wrong baudrate or uses two stopbits instead of one. But this is not unique for HT, your app should react the same way by getting nonsense.
If I were you I would get an oscilloscope or logic analyser to see what's really going on with the RxD and TxD lines.

--
Roger

Aditi48415-Sep-05 21:51

How to add a Scheduled Task to the Task Scheduler

15-Sep-05 21:51

Thank you for your reply.. Sorry i'm only getting back now.. I was busy tweaking the code and the MC to see where the problem was.. turns out it was the MC.. there was problems with synchronization when talking to the PC..

Thank you all for your time to help.. I've sure have learnt some pointers from the replies..

PravinSingh12-Sep-05 23:55

PravinSingh

12-Sep-05 23:55

I want to write a program that makes a particular exe run everyday. For this, it should add that exe to Scheduled Tasks. But how to do that programatically?

All I know is, when we add a new Scheduled Task, say MyTask, it creates a file "C:\Windows\Tasks\MyTask.job", but this file contains some binary data and can't be directly created/editad.

Any Standard Ways / Workarounds ?

It's better to know some of the questions than all of the answers.

Pravin.

Re: How to add a Scheduled Task to the Task Scheduler

prasad_som13-Sep-05 0:03

prasad_som

13-Sep-05 0:03

You need to use ITaskScheduler interface.
You can easily come to know how to use it, and there are related interfaces.

Re: How to add a Scheduled Task to the Task Scheduler

David Crow13-Sep-05 2:30

David Crow

13-Sep-05 2:30

Here's a starting point:

HRESULT hr = CoInitialize(NULL);
if (SUCCEEDED(hr))
{
    ITaskScheduler *pITaskScheduler = NULL;
 
    hr = CoCreateInstance(CLSID_CTaskScheduler, NULL, CLSCTX_INPROC_SERVER, IID_ITaskScheduler, (void **) &pITaskScheduler);
    if (SUCCEEDED(hr))
    {
        ...
        pITaskScheduler->Release();
    }
 
    CoUninitialize();
}

See here for more.

"One must learn from the bite of the fire to leave it alone." - Native American Proverb

memory management

Ali Tavakol12-Sep-05 23:55

Ali Tavakol

12-Sep-05 23:55

I don't understand why NT uses a 2-step physical memory locating method. it splits a 32-bit virtual address in 3 parts. two first parts are indexes of page-directory and page-table respectively.
why dosn't it split virtual adress in 2 parts in which the fist part only indexs page table index and the CR3 register points to the first index of page table?
please explain more and more!!

server and client

Member 216100412-Sep-05 23:54

Member 2161004

12-Sep-05 23:54

I have a simple server and client source code that can run. The problem is I type two same IP address in the source code of server and client, the program can connect and send. But when I test the program in two PC and type both IP address in both of the program, the program cannot work. What is the problem of it?

CDC::SelectObject

Nishad S12-Sep-05 23:33

Nishad S

12-Sep-05 23:33

Hello,

It is said in MSDN for the SDK SelectObject fn that "An application should always replace a new object with the original, default object after it has finished drawing with the new object".

Is it neccessary for MFC CDC object also?

- NS -

Re: CDC::SelectObject

ThatsAlok12-Sep-05 23:48

ThatsAlok

12-Sep-05 23:48

Nishad S wrote:
Is it neccessary for MFC CDC object also?

Why Not??

"Opinions are neither right nor wrong. I cannot change your opinion. I can, however, change what influences your opinion." - David Crow

cheers,
Alok Gupta
VC Forum Q&A :- I/ IV

Re: CDC::SelectObject

John R. Shaw13-Sep-05 5:48

John R. Shaw

13-Sep-05 5:48

Yes!

The CDC object is just a wrapper around a DC handle and it provides minimal support for reading/writing to a DC handle, as it should.

INTP
"The more help VB provides VB programmers, the more miserable your life as a C++ programmer becomes."
Andrew W. Troelsen

Limited number of controls on a dialog?

Mircea Puiu12-Sep-05 22:27

Mircea Puiu

12-Sep-05 22:27

Hi all,

Has any ever encountered this kind of problem when usin VC6:
On the surface of the main dialog, tthere are 129 controls (CStatic's, CEdit's, CButton's).
No other resource can be added on the dialog surface (neither by resource selecting and insertion, nor by copy-paste merthod) ?

Thanks

SkyWalker

toxcct12-Sep-05 22:30

toxcct

12-Sep-05 22:30

the number of controls that can be added in design mode is limited to 255 due to the resource identifiers.

if you want more, you will have to add your controls dynamically/programmatically.

TOXCCT >>> GEII power
[toxcct][VisualCalc]

Mircea Puiu12-Sep-05 22:52

Mircea Puiu

12-Sep-05 22:52

I can understand that, but why is it working if I manually add them in the .rc file (using Notepad for that) ?

( I did not have 255 identifiers yet Frown | :-(

)

SkyWalker

toxcct12-Sep-05 22:55

toxcct

12-Sep-05 22:55

Mircea Puiu wrote:
using Notepad for that

why doun't you just use the resource editor ??????

check however to resource.h file to verify that the coutrols have consecutive IDs.

TOXCCT >>> GEII power
[toxcct][VisualCalc]