Re: string - C / C++ / MFC Discussion Boards

Re: string

macmac3822-Apr-04 2:13

macmac38

22-Apr-04 2:13

while(port.Read(cReceivedChar, 1 , overlapped, &dwBytesRead))

Thanks, Mark

Re: string

David Crow22-Apr-04 2:15

David Crow

22-Apr-04 2:15

The first parameter is supposed to be a pointer.

"The pointy end goes in the other man." - Antonio Banderas (Zorro, 1998)

Re: string

macmac3822-Apr-04 2:32

macmac38

22-Apr-04 2:32

<br />
<br />
char *cReceivedChar;<br />
<br />
while(port.Read(cReceivedChar, 1, overlapped, &dwBytesRead))

Thanks, Mark

Re: string

David Crow22-Apr-04 2:52

David Crow

22-Apr-04 2:52

But then you'd have to allocate one byte of memory from the heap (i.e., cReceivedChar = new char). Why not just use this instead:

char cReceivedChar;
while(port.Read(&cReceivedChar, 1, overlapped, &dwBytesRead)) 
    ...

"The pointy end goes in the other man." - Antonio Banderas (Zorro, 1998)

Re: string

macmac3823-Apr-04 2:26

macmac38

23-Apr-04 2:26

yep, it seems to be better to use a reference.

with this procedure my string output is only "0.1922"

remember incoming:

924.09,-4.06,676.26,0.156488,-0.653856,-0.714853,-0.192273

It looks like that the first values running through the digits in the dialog..mmh?? Is this so complicate to give out the full string?

Thanks, Mark

Re: string

David Crow23-Apr-04 3:35

David Crow

23-Apr-04 3:35

macmac38 wrote:
yep, it seems to be better to use a reference.

My example was not a reference. It was a pointer, exactly what the Read() method is expecting. Had it wanted a reference, the signature would look like:

BOOL Read(void& lpBuf, ...);

You mentioned that 924.09,-4.06,676.26,0.156488,-0.653856,-0.714853,-0.192273 is arriving at the serial port. How are you verifying this?

"The pointy end goes in the other man." - Antonio Banderas (Zorro, 1998)

Re: string

macmac3823-Apr-04 3:55

macmac38

23-Apr-04 3:55

This is the position string from a robot arm and every time the same format.

x,y,z shift and quaternion 1-4

I have to extract them later from the string in float variables

Thanks, Mark

Re: string

David Crow23-Apr-04 4:15

David Crow

23-Apr-04 4:15

That's all well and good, but in your original post, you indicated that "This arrives at my serial port," implying that the data is indeed there. That's why I asked how you were verifying it.

In the while loop that you are using to read the incoming data, how many times does the loop execute?

After each call to Read(), what is the value of dwBytesRead?

If the incoming data is always in the same format and is always less than X bytes, you might could use this instead:

char received[X];
port.Read(received, sizeof(received), overlapped, &dwBytesRead);
received[dwBytesRead] = '\0';

"The pointy end goes in the other man." - Antonio Banderas (Zorro, 1998)

Re: string

macmac3823-Apr-04 5:01

macmac38

23-Apr-04 5:01

<br />
received[dwBytesRead] = '\0';<br />

what does this line mean? I have "access violation" with this line.

Thanks, Mark

Re: string

David Crow23-Apr-04 5:26

David Crow

23-Apr-04 5:26

macmac38 wrote:
what does this line mean?

It appends a \0 character to the end of the string.

macmac38 wrote:
I have "access violation" with this line.

How big is the received array, and what is the value of dwBytesRead?

"The pointy end goes in the other man." - Antonio Banderas (Zorro, 1998)

Re: string

macmac3823-Apr-04 6:17

macmac38

23-Apr-04 6:17

<br />
 char received[40];<br />
	  <br />
 port.Read(received, sizeof(received), overlapped, &dwBytesRead);<br />
<br />
          TRACE( "Bytes read: %d",dwBytesRead);<br />
	  <br />
	  received[dwBytesRead] = '\0';<br />
       <br />
	  SetDlgItemText(IDC_SHIFT_X, received);<br />
<br />

Bytes read: 1Bytes read: -858993460Bytes read: -858993460Bytes read: -858993460

Thanks, Mark

Re: string

David Crow23-Apr-04 6:40

David Crow

23-Apr-04 6:40

macmac38 wrote:
TRACE( "Bytes read: %d",dwBytesRead);

Since dwBytesRead is a DWORD, you'll need to use the %lu format.

Nonetheless, if received[] is only 40 bytes, trying to access the -858993460th position, or any value outside of 0-39, is obviously wrong. Check the return value of Read() beforehand.

In your original post, you indicated that 58 characters were being sent to the serial port. You'll need room for that plus one more so received[] should be 59 not 40. This is not the root of the problem, however, but will eventually need to be addressed.

"The pointy end goes in the other man." - Antonio Banderas (Zorro, 1998)

Re: string

macmac3825-Apr-04 22:47

macmac38

25-Apr-04 22:47

<br />
<br />
	  char received[59];<br />
<br />
	  port.Read(received, sizeof(received), overlapped, &dwBytesRead);<br />
<br />
	  <br />
      TRACE( "Bytes read: %lu",dwBytesRead);<br />
	  <br />
	  received[dwBytesRead] = '\0';<br />
       <br />
	  SetDlgItemText(IDC_SHIFT_X, received);<br />

Bytes read: 1

I donn't know where's the problem? Normaly it seems easy..?
Like to solve it today Wink | ;-)

Thanks, Mark

Re: string

David Crow26-Apr-04 2:18

David Crow

26-Apr-04 2:18

macmac38 wrote:
I donn't know where's the problem?

Are you sure a problem exists? Maybe there was only one byte available to read.

"The pointy end goes in the other man." - Antonio Banderas (Zorro, 1998)

Re: string

macmac3826-Apr-04 2:25

macmac38

26-Apr-04 2:25

But this Byte output like: j
which means no character in it?
But the full string is arriving..

if i don't use this line:

received[dwBytesRead] = '\0';

the output is:

-0.714853,-0.192273jjjjjjjjjjjjjjjjj

Thanks, Mark

Re: string

David Crow26-Apr-04 2:31

David Crow

26-Apr-04 2:31

macmac38 wrote:
But the full string is arriving..

How are you verifying this claim?

Whct class does the Read() method belong to? I'm curious if the fourth parameter is being used correctly. If more than one byte is being read, yet dwBytesRead equals 1, something is awfully wrong. It might also be the third parameter, but I've never used the OVERLAPPED structure before so I can't say for sure.

"The pointy end goes in the other man." - Antonio Banderas (Zorro, 1998)

custom resource problem

chocm20-Apr-04 23:36

chocm

20-Apr-04 23:36

I created a custom resource in the SDI project, in other words, there is a new folder named "MyText" under the "MyView recources" in the resource view workspace , and there is an entry named "IDR_MYTEXT1" in the "MyText" folder. The content of IDR_MYTEXT1 is imported from a text file. I want to show the text file in the view window. but some error occured, I can't see the text file content at all.

Thanks for help in advance!

void CMyView::OnInitialUpdate()
{
CView::OnInitialUpdate();
HRSRC hrsrc=::FindResource(::AfxGetApp()->m_hInstance,"IDR_MYTEXT1","MyText");

HGLOBAL hglb=::LoadResource(::AfxGetApp()->m_hInstance,hrsrc);
LPVOID m_ptr=::LockResource(hglb);

}

void CMyView::OnDraw(CDC* pDC)
{
CMy0421Doc* pDoc = GetDocument();

ASSERT_VALID(pDoc);
pDC->TextOut(0,0,"I insert a text file as a custom resource, and show it in the SDI program");

pDC->TextOut(100,100,(char*)m_ptr);

}

Have you tried Internet Telephone Services[^]

Re: custom resource problem

David Crow21-Apr-04 2:52

David Crow

21-Apr-04 2:52

chocm wrote:
...but some error occured

And that error would be what?

In the OnInitialUpdate() method, you have a local variable named m_ptr. How are you expecting to access this variable from within the OnDraw() method?

"The pointy end goes in the other man." - Antonio Banderas (Zorro, 1998)

Re: custom resource problem

chocm21-Apr-04 18:46

chocm

21-Apr-04 18:46

m_ptr is a member variable of CMyView, so I think it is valid in the OnDraw();

Re: custom resource problem

David Crow22-Apr-04 2:05

David Crow

22-Apr-04 2:05

So change the LPVOID m_ptr=::LockResource(hglb) statement to m_ptr=::LockResource(hglb) instead.

"The pointy end goes in the other man." - Antonio Banderas (Zorro, 1998)

Re: custom resource problem

chocm22-Apr-04 18:26

chocm

22-Apr-04 18:26

Yes I have change the line to m_ptr=::LockResource(hglb), the problem is still the same, no text file was shown as expected.

I tried to set a breakpoint at the line:
HGLOBAL hglb=::LoadResource(::AfxGetApp()->m_hInstance,hrsrc);

and then pressed the button Go, in the output window, I got hrsrc's value is 0X00000000, clicked to extract the button left to the "hrsrc", there is some info shown as "unused CXX0030: Error: expression can't be evaluated"

the hglb's vaule is 0xcccccccc

Does the FindResource() work improperly? I need more suggestions, Thanks!

Re: custom resource problem

David Crow23-Apr-04 2:08

David Crow

23-Apr-04 2:08

chocm wrote:
Does the FindResource() work improperly?

Not if it is used correctly. If it, or LoadResource() are returning NULL, call GetLastError() to find out why.

"The pointy end goes in the other man." - Antonio Banderas (Zorro, 1998)

Re: custom resource problem

chocm24-Apr-04 23:20

chocm

24-Apr-04 23:20

I was told to add the MAKEINTRESOURCE to the parametre in the function FindResource(), Then all the code began to work properly.

FindResource(::AfxGetApp()->m_hInstance,MAKEINTRESOURCE(IDR_MYTEXT1),"MYTEXT");

Another question, under what condition is the MAKEINTRESOURCE necessary?

Re: custom resource problem

David Crow26-Apr-04 2:20

David Crow

26-Apr-04 2:20

chocm wrote:
Another question, under what condition is the MAKEINTRESOURCE necessary?

See here.

"The pointy end goes in the other man." - Antonio Banderas (Zorro, 1998)

How to scroll CListView down ?

vgrigor20-Apr-04 23:26

vgrigor

20-Apr-04 23:26

I need to scroll CListView to bottom.

How to do it?

thanks.

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.