C / C++ / MFC

Re: Access Violation at ii=ii+1; all other variables print value correctly

25-Jan-08 13:10

// select suitable seedwave file for the deck
CString file_now;
s_dis=0;
int ii=0;
file_now=ftitle[0];
s_dis=sd_dis[0];
//
do {
file_now=ftitle[ii];
s_dis=sd_dis[ii];
//
ii =ii+1;
//
} while (ii<nfile && sd_dis[ii]<dis);
//

I debudg my program I got "Access Violation" at ii=ii+1; all other variables print value correctly. I really do not know what is the problem ?

Thanks for the help

David Crow25-Jan-08 17:13

Re: Access Violation at ii=ii+1; all other variables print value correctly [modified]

25-Jan-08 17:13

mrby123 wrote:
I debudg my program I got "Access Violation" at ii=ii+1;

What is the value of ii at this point?

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mrby12325-Jan-08 20:37

Re: Access Violation at ii=ii+1; all other variables print value correctly

25-Jan-08 20:37

at this point ii=0. However, if the statement would exicute, ii should be 1.
However, access violation occured when the statement was tried to exicute.
You can see I initialized ii before the block.

Thanks

modified on Saturday, January 26, 2008 2:54:41 AM

CPallini25-Jan-08 21:44

CPallini

25-Jan-08 21:44

I think you should post also array declarations.
Smile | :)

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-- Alfonso the Wise, 13th Century King of Castile.

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Re: Access Violation at ii=ii+1; all other variables print value correctly

mrby12326-Jan-08 7:18

Re: Access Violation at ii=ii+1; all other variables print value correctly

26-Jan-08 7:18

Thanks for your response.

Here is the array declarations:

float sd_dis[20];
CString ftitle[20];
//
CString file_now;
s_dis=0;
int ii;
ii=0;
do {
file_now=ftitle[ii];
s_dis=sd_dis[ii];
ii =ii+1;
} while (ii<nfile && sd_dis[ii]<dis);
//

CPallini26-Jan-08 22:51

CPallini

26-Jan-08 22:51

Well, of course ii=ii+1; cannot give such an exception, you have to check, using the debugger, for out-of-boundary array access, i.e. if ii happen to be 20 or more in code containing sd_dis[ii] or ftitle[ii].

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

[my articles]

Re: Access Violation at ii=ii+1; all other variables print value correctly

mrby12327-Jan-08 14:01

Re: Access Violation at ii=ii+1; all other variables print value correctly

27-Jan-08 14:01

Thanks for the comments:

I can not find anything like "if ii happen to be 20 or more in code containing sd_dis[ii] or ftitle[ii].". At ii=ii+1 the error pointed in the debudg at the following statement:

->> 00433872 mov dword ptr [ecx],edx

Thanks for the help

CPallini27-Jan-08 22:18

CPallini

27-Jan-08 22:18

Could please post the whole error message (and the whole code snippet)?
What is the ii value when the exception occurs?
BTW the assembly instruction reported doesn't appear to be an integer increment operation: it seems more an array access.
Smile | :)

If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.

[my articles]

strcpy_s vs strncpy_s (VC 2005 Secure API's)

Peter Weyzen25-Jan-08 11:10

Peter Weyzen

25-Jan-08 11:10

We used to use strncpy to protect the buffer when copying into it. Does strcpy_s totally take that over?

I know when I debug, that sometimes I get a runtime error inside strcpy_s when the source string is longer than the buffer.

Will this runtime error appear in a non-debug build?

And should I really be using strncpy_s() instead of strcpy_s()?

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~<br />
Peter Weyzen<br />
Staff Engineer<br />
<a href="http://www.soonr.com">SoonR Inc -- PC Power delivered to your phone</a>

Re: strcpy_s vs strncpy_s (VC 2005 Secure API's)

David Crow25-Jan-08 17:17

Re: strcpy_s vs strncpy_s (VC 2005 Secure API's)

25-Jan-08 17:17

Peter Weyzen wrote:
And should I really be using strncpy_s() instead of strcpy_s()?

Only if you need to tell the function how many characters to copy.

Peter Weyzen25-Jan-08 20:04

Peter Weyzen

25-Jan-08 20:04

I guess it was the exception inside strcpy_s that got me.

I hope that's debug only....

What's your opinion of the _s funtions? They seem long overdue...

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~<br />
Peter Weyzen<br />
Staff Engineer<br />
<a href="http://www.soonr.com">SoonR Inc -- PC Power delivered to your phone</a>

Re: strcpy_s vs strncpy_s (VC 2005 Secure API's)

Nemanja Trifunovic26-Jan-08 8:25

Nemanja Trifunovic

26-Jan-08 8:25

Peter Weyzen wrote:
What's your opinion of the _s funtions? They seem long overdue...

Non-portable, slow and also not very secure either.

Programming Blog

utf8-cpp

Finding an SMTP server

hxhl9525-Jan-08 11:02

25-Jan-08 11:02

Hi all,

I've see apps before where you click a button and it shows you a listbox with local SMTP server(s). How exactly is this done? I've done some research into querying MX records, and also the DnsQuery function in Windows, but they don't help at all.

Can anyone give me some pointers?

Thanks in advance. Smile | :)

David Crow25-Jan-08 17:21

25-Jan-08 17:21

hxhl95 wrote:
How exactly is this done?

DnsQuery() is but one way.

PDNS_RECORD pRec = NULL;
DnsQuery(lpszHostDomain, DNS_TYPE_MX, DNS_QUERY_STANDARD, NULL, &pRec, NULL);

hxhl9525-Jan-08 19:42

25-Jan-08 19:42

How would I find the host domain though?

David Crow26-Jan-08 12:06

Re: Finding an SMTP server [modified]

26-Jan-08 12:06

Can't you use whatever domain you are sending the e-mail to?

hxhl9526-Jan-08 16:39

26-Jan-08 16:39

I could, but I've seen apps where they get the local domain...I'm just curious. I mean, of course it would work to get the domain of the recipient's email(s), but I'd like to know how you get the local domain name.

And...to use DnsQuery you have to include WinDNS.h and add dnsapi.lib to your library files, right? I've added dnsapi.lib in, but my VC++ 6.0 compiler tells me that it can't find the file. Why? (I've installed the SDK already)

modified on Saturday, January 26, 2008 11:21:58 PM

David Crow27-Jan-08 8:39

27-Jan-08 8:39

hxhl95 wrote:
...but my VC++ 6.0 compiler tells me that it can't find the file. Why?

Is your SDK's Include folder known by the IDE (it's not by default)? If you use an absolute path with dnsapi.lib, does that satisfy the linker?

hxhl9527-Jan-08 10:45

27-Jan-08 10:45

Yeah, the IDE knows the include folder's path. I added it in.

Apparently though, everything works without Dnsapi.lib. MSDN told me that DnsQuery needed dnsapi.lib, but I guess not. Big Grin | :-D

So one question remains: Is there any way to obtain the local domain?

David Crow28-Jan-08 2:31

28-Jan-08 2:31

hxhl95 wrote:
...but I guess not.

So what other library do you suppose its hiding in?

hxhl95 wrote:
So one question remains: Is there any way to obtain the local domain?

You can use NetWkstaGetInfo() for this.

hxhl9531-Jan-08 13:26

31-Jan-08 13:26

About NetWkstaGetInfo():

LPWKSTA_INFO_100 netinfo = NULL;<br />
	if (NetWkstaGetInfo(NULL,100,(LPBYTE*)netinfo)!=NERR_Success){<br />
		MessageBox("Error");<br />
		return;<br />
	}

I get the messagebox each time. Any clues as to why the function isn't getting the info properly? I debugged, and past the NetWkstaGetInfo line, netinfo points to 0x00000000...Definitely not correct. Sigh | :sigh:

Thanks for all your help.

David Crow31-Jan-08 16:16