ping Elysia, the VC++ expert :)

Would you happen to have a link to a good tutorial on how to use VC++ 2008 Express to debug C programs?

The online help that came with VC++ gives a short(simple) tutorial on how to debug a basic C++ program, so all the debugging tools and codes are related to C++.

I am a C newbie, and would like instructions(as comprehensive as possible) relevant to C, which I can at least partially understand.

Thanks in advance. :)

Set breakpoint(s) with F9, use F10 (step over) and F11 (step into) to step around the code. F5 runs to the next breakpoint.

There are other things you can do, but with those few things, you have a starting point.

If you have a crash, the "call stack" window is good to see how you ended up where you ended up [unless you have made a REAL mess of things].

--
Mats

Thanks Mats. :)

Also, Shift+F11 is step out (running to the end of a function).
All the commands are available through the Debug menu.
Pay attention to the variables window, as well. You can select Auto or Watch, to manually select which variables to watch.
You can also hover the mouse over variables to see their contents.

There are lots of things a debugger can do, but these are the basics. If you need help tracking down a problem, we can explain additional techniques you can use.

Thanks Elysia. :)

I am going to devote 1-2 weeks learning how to use the debugger.

Quote:

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Originally Posted by matsp

If you have a crash, the "call stack" window is good to see how you ended up where you ended up [unless you have made a REAL mess of things].

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In my "call stack" window, are these 5 lines:

Quote:

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> test.exe!main() Line 37 C
test.exe!__tmainCRTStartup() Line 586 + 0x19 bytes C
test.exe!mainCRTStartup() Line 403 C
kernel32.dll!7c817067()
[Frames below may be incorrect and/or missing, no symbols loaded for kernel32.dll]

---

The only thing that changes when I keep pressing F10 is the line number, and the bottom 2 lines are permanently greyed out.

Should there be alot more happening in this window? :)

And for the pointers that I've declared, in the "Autos" window, I get:

Quote:

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+ p_line 0xcccccccc <Bad Ptr> char *
+ p_newline 0xcccccccc <Bad Ptr> char *

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But I think it's because they haven't been initialised yet?

Thanks. :)

Quote:

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Code:

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> test.exe!main() Line 37 C
test.exe!__tmainCRTStartup() Line 586 + 0x19 bytes C
test.exe!mainCRTStartup() Line 403 C
kernel32.dll!7c817067()
[Frames below may be incorrect and/or missing, no symbols loaded for kernel32.dll]

---

---

Typically we don't care about anything below main().

The call stack is just telling you that you are on Line 37 in main().

Thanks cyberfish. :)

Here's something that some may find interesting.

I did a little research on the net, and have found that the symbols that is required by the debugger does not come packaged with Visual Studio.

So you have to set the debugger to download the symbols from the M$ symbol server, and there are 2 ways to do this, automatically, or manually. These instructions are directly from the VC++ online help.

Automatically

1.On the Debug menu, click Options.

2.In the Options dialog box, open the Debugging node, and then click Symbols. For more information, see How to: Specify a Symbol Path.

3.Edit the text to add a new path to the symbol server.

To use the Microsoft public symbol server, type:

http://msdl.microsoft.com/download/symbols (this is not browseable, and can only be accessed by the debugger for downloading).

Manually
Right-click in the Modules window and choose Find Symbols on the shortcut menu.

The debugger searches the symbol path to try to find symbols itself. If symbols were not found, the Find Symbols dialog box appears. In the Find Symbols dialog box, locate the symbols file (PDB or DBG file) you want to load. When the name of the symbols file appears in the File Name box, click OK.

Now my 'call stack' window looks like this:

Quote:

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> test.exe!main() Line 19 C
test.exe!__tmainCRTStartup() Line 586 + 0x19 bytes C
test.exe!mainCRTStartup() Line 403 C
kernel32.dll!_BaseProcessStart@4() + 0x23 bytes

---

The debugger will download whatever symbols are needed for whatever dll is required(ie. kernel32.dll). Don't know what, if any use it is to me, but at least the debugger is getting what it needs, and I don't see this anymore

Quote:

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kernel32.dll!7c817067()
[Frames below may be incorrect and/or missing, no symbols loaded for kernel32.dll]

---

Time for me to play some more with the debugger. :)

Quote:

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Originally Posted by happyclown

And for the pointers that I've declared, in the "Autos" window, I get:
But I think it's because they haven't been initialised yet?

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Yes, as you can see, the debugger will automatically try to dereference any pointers it encounters and display its value. In this case, the pointers aren't initialized (in Debug mode, all variables are automatically initialized to 0xCC...). You can click on the plus to see what it's pointing to, if it's a valid pointer. If the pointer you dereference points to a struct that contains more pointers of if it's a pointer to pointer, you can dereference the other pointers and see where they lead, etc, into eternity.

Variables that have been destroyed and pointers that have been freed are filled with 0xFEFEFEFE.

I am trying to debug this program

Code:

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/* Passing an array to a function. Alternative way. */

#include <stdio.h>

#define MAX 10

int array[MAX+1], count;

int largest(int num_array[]);

int main( void )
{
    /* Input MAX values from the keyboard. */

    for (count = 0; count < MAX; count++)
    {
        printf("Enter an integer value: ");
        scanf("%d", &array[count]);

        if ( array[count] == 0 )
            count = MAX;              /* will exit for loop */
    }
    array[MAX] = 0;

    /* Call the function and display the return value. */
    printf("\n\nLargest value = %d\n", largest(array));

    return 0;
}
/* Function largest() returns the largest value */
/* in an integer array */

int largest(int num_array[])
{
    int count, biggest = -12000;

    for ( count = 0; num_array[count] != 0; count++)
    {
        if (num_array[count] > biggest)
            biggest = num_array[count];
    }

    return biggest;
}

---

In the "Autos" window, the only variable shown is count, and it's value. Why isn't array[count](and it's value) shown as well? If I was to run the mouse over array[count], I can see it's value, but I would like to see it's value as the program is running. Other programs that I've debugged show ALL values of arrays, and pointers, as they are assigned, so why isn't that happening in this case?

Thanks. :)

"Auto" isn't always automatic. Use manual watching instead.
Highlight the variable, right-click and select Add Watch. Then turn to your Watch window beside the Auto window. Here you can see all the variables you have specified to watch.

Oh and global variables are bad. That might be one of the reasons that debugger is ignoring it ;)

o.o ok... I really just thought Visual C++ was a text editor with intellisense(?) and a compiler... Didn't know it was so advanced and stuff, I should start learning this ;)

Code:

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        if ( array[count] == 0 )
            count = MAX;              /* will exit for loop */

---

If you want to break a loop, use "break", not changing the loop variable - it can confuse the compiler, and is definitely harder to follow for humans.

--
Mats

Visual Studio is a complete developer package. It contains compiler, debugger, editor, code analysis, testing, source server, and much more, depending on version.
There is a reason companies use it over any other IDE.
But for non-professional developers, most of those extra features are overkill. Although, that is not to say testing and code analysis are bad things.

source server o.o? Any explaination to that? Like, do you get a server where you can save your source, and others in the team(if you have one) can just download and upload to it o.o?
If that's it, then it's the ultimate team working benefit, or something! And I've been looking for such a thing for quite sometime xP but I guess it's not in the express version?

Quote:

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Originally Posted by Akkernight

source server o.o? Any explaination to that? Like, do you get a server where you can save your source, and others in the team(if you have one) can just download and upload to it o.o?

---

Yes, that's the idea of a source server. To get several people working on the same source.

Quote:

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If that's it, then it's the ultimate team working benefit, or something! And I've been looking for such a thing for quite sometime xP but I guess it's not in the express version?

---

Unfortunately, no.
It's in Team Server Edition or something like that. Verrrrrrrrrry expensive stuff :/

Damn mass money making bastards >.> Anyone have any other place where this is possible?

It's aimed at companies, so of course it's expensive.

Quote:

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Originally Posted by Akkernight

Anyone have any other place where this is possible?

---

Where what is possible?

Yeah I know, still, Microsoft doesn't need the money D: meh, it'd be awsome to have something like that, 'cause sending source code through Instant Messengers or bad free upload sites, is extremely frusterating >.>

EDIT: To upload source code, and others of a team can download and upload easily and stuff...

That's what subversion is for. Kinda.
How to get a subversion server, I do not know, but I do know of clients that use it.

subversion o.O? wut the hell is this? Where do I get info about this? Off to Google!

I think Elysia is referring to the source control system that is included in the more advanced versions of Visual Studio: SourceSafe.

A version control system is an excellent way to keep track of what you've been doing with the source code - and getting back to a working version when you messed up.

--
Mats

Ah, Mats probably knows more specifics about this than I. I have never used any of it.
Wonder if VS works with subversion?

Read about subversion, and know I know of it :D It's svn, right? Used turtoiseSVN kinda much ;) Imma get to that this weekend ^^

Quote:

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Originally Posted by Akkernight

To upload source code, and others of a team can download and upload easily and stuff.

---

If it was so simple, it would be a scam since any server would do. Looking at this article that claims that Source Server Helps You Kill Bugs Dead In Visual Studio 2005*, it apparently works with version control, and one of the aims is to coordinate the task of debugging among different developers.

* heh, the title makes it seem as if you should use Source Server to debug bugs in Visual Studio 2005 that should have already been fixed by the developers :D

Quote:

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Originally Posted by Elysia

That's what subversion is for. Kinda.
How to get a subversion server, I do not know, but I do know of clients that use it.

---

No, the rough equivalent of Subversion offered by Microsoft is Visual Source Safe, not Source Server, and from what I understand Visual Source Safe does not keep your source safe (as in it is known for data corruption). Personally, I use Bazaar :p

EDIT:

Quote:

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Originally Posted by Elysia

Wonder if VS works with subversion?

---

Yes, it does, but I was not satisfied with the plugin.

Bazaar o.O? I've heard that name... Off to Google again! xD

Quote:

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Originally Posted by laserlight

from what I understand Visual Source Safe does not keep your source safe (as in it is known for data corruption).

---

I have currently projects that are still stored in SS (From VS6.0 Enterprise) more than 10 years long. I'm not familiar with any data loss in my firm due to usage of SS. And I'm sure - if some loss would occure in the past all the projects were moved to some alternative vesion control system

Currently all new projects are managed with ClearCase that is a lot more advanced than SS and has its own drawbacks due to complexity and performance issues.

I'm aware of several projects arond the firm that are trying different version control systems. So far no one of them is accepted as a mainstream version control database

SourceSafe is fine if you have a local server. Where I worked about 5 years back, they had problems when an office in the US got connected to the SourceSafe server in the UK - apparently, it doesn't have very good safety on the packets.

--
Mats

Wikipedia on Revision Control

I found this PDF quite helpful in explaining the basics of Visual Studio Debugger, so I will think other VS newbies will also find it a good start too. :)

http://webpages.uncc.edu/~rguzzo/Deb...l%20Studio.pdf

And here is the .html version of the above PDF, without the diagrams(which you will need to see what is being discussed).

http://209.85.175.132/search?q=cache...lnk&cd=1&gl=au

Quote:

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Originally Posted by matsp

SourceSafe is fine if you have a local server. Where I worked about 5 years back, they had problems when an office in the US got connected to the SourceSafe server in the UK - apparently, it doesn't have very good safety on the packets.

--
Mats

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Agree, working with SS over the internet link is head ache

I have to keep using this code in every source file that I compile, to turn off VC++ 2008 deprecation warnings.

Code:

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#define _CRT_SECURE_NO_WARNINGS

---

EDIT:

The types of deprecation warnings are:

Quote:

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warning C4996: 'fopen': This function or variable may be unsafe. Consider using fopen_s instead. To disable deprecation, use _CRT_SECURE_NO_WARNINGS. See online help for details.

---

Is there an option in VC++ where I can make it turn off the warnings as a default?

Thanks. :)

Quote:

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Originally Posted by happyclown

Is there an option in VC++ where I can make it turn off the warnings as a default?

---

Yes. Project -> Properties -> Configuration Properties -> C/C++ -> Preprocessor -> Preprocessor Definitions. Write _CRT_SECURE_NO_WARNINGS in the corresponding input form control.

Quote:

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Originally Posted by laserlight

Yes. Project -> Properties -> Configuration Properties -> C/C++ -> Preprocessor -> Preprocessor Definitions. Write _CRT_SECURE_NO_WARNINGS in the corresponding input form control.

---

Thanks laserlight. :)

How do I set the debugger to target a specific directory? I normally put the executable into the target directory.

I've tried putting all the files that my program needs to open into the Debug directories(why are there 2 Debug directories?) in the project folder, but the debugger isn't opening the files.

It's giving the error message "no such files or directories".

I tried playing with the project properties, "Working Directory" and "Environment", but that didn't work.

Thanks in advance. :)

EDIT: Ok, I tried "working directory" properties again, and now it works. No idea why it didn't work before.