C / C++ / MFC

David Crow30-Apr-20 3:50

David Crow

30-Apr-20 3:50

Richard MacCutchan wrote:

I also could not find the TRACE macro in Windows.

Isn't that an MFC thing?

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Richard MacCutchan30-Apr-20 4:02

30-Apr-20 4:02

Could be, but I haven't used MFC since about 2003, and I don't intend doing so ever again.

Victor Nijegorodov30-Apr-20 5:55

Victor Nijegorodov

30-Apr-20 5:55

Richard MacCutchan wrote:
I also could not find the TRACE macro in Windows.

After a lot of calls... it finishes calling _CrtDbgReportW

Richard MacCutchan30-Apr-20 6:00

30-Apr-20 6:00

It's an MFC* macro (as pointed out by David Crow above).

*Yes, I know, that combination of letters should no more pass my lips.

David Crow30-Apr-20 3:50

David Crow

30-Apr-20 3:50

Like they say in the movies, the names have been changed to protect the innocent.

_Flaviu30-Apr-20 6:09

_Flaviu

30-Apr-20 6:09

kalberts30-Apr-20 17:45

kalberts

30-Apr-20 17:45

I am really puzzled by how difficult it seem to be to explain how the value of that .directory was initialized. Where its value came from. How it was created.

Obviously, whatever created the value did not follow the C convention of terminating it with a nul - most likely because it doesn't have a C origin. Fair enough. But why is it so difficult to show how the .directory value was obtained?

As it now stands, it is like complaining "This variable should have av value between 0 and 100, but it is above 100. Why???" If you can't figure that out yourself, you must reveal how you calculate it, you cannot simply tell us how you use it, after it has gotten that out-of-range value-

Your directory string is another out-of-range value. How you use it, after it got this illegal value is of no interest. The important thing is how it got that value, not how you later use it. Like if you ask "Why does my value exceed 100?" Noone can tell unless you tell how you got or calculated that value. String values are no different: If they have an illegal value, such as not being nul-terminated in contexts where that is expected, the problem is in the source, not in the use of the value.

If it is as difficult as it seems to trace the source, identify where that directory sting came from, then you should not expect others to be able to help you. "I have an illegal value, but I can't tell where it came from - why is it not legal?" - noone can give you a reasonable answer to that.

So come on, tell us how the .directory value was obtained/created! Until you do that, you cannot expect any useful help from other forum members

Richard MacCutchan1-May-20 4:02

1-May-20 4:02

I think you may be banging your head against a brick wall. I have tried this approach repeatedly and got nowhere. But well done for trying.

_Flaviu1-May-20 4:48

_Flaviu

1-May-20 4:48

I'll try myself the piece of code that I am putting here, by now I have taken the code from real project. I come back soon. I only need to move those structures in a test app and make it run.

modified 1-May-20 11:17am.

_Flaviu3-May-20 5:21

_Flaviu

3-May-20 5:21

Here is what I've discovered by now:

C++

dir_data_t directory_data;
strncpy(directory_data.current_directory, "/", sizeof(directory_data.current_directory));

directory_data is ok by now.

C++

struct list_head* filewalker = NULL;
file_info_t dirlist;
logdir(&directory_data, &dirlist);
INIT_LIST_HEAD(&dirlist.list);
const file_info_t* current_file = NULL;
list_for_each(filewalker, &dirlist.list)
{
	current_file = list_entry_const(filewalker, const file_info_t, list);
	TRACE(_T("current_file->name %s\n"), current_file->name); // ->> now, sometime, current_file->name has a value like that: Oe©*BºcE«Mò×¦£š{@Q—Y|†Š˜b!    and from now one, everything goes bad
}

after that,

C++

strcat(directory_data.current_directory, current_file->name);

is not ok, of course. INIT_LIST_HEAD, list_for_each and list_entry_const are Linux functions. logdir functions I could not reproduced in a test app or write here because has many dependencies ... and to be everything more complicated, all this code is written in a recursive function .... is quite difficult to reproduced this situation in a test app ... I am trying to explore logdir function to see what I find there ...

Richard MacCutchan7-May-20 4:34

Passing an array as argument to a function (2)

7-May-20 4:34

That looks quite likely that some entries in your list are either corrupt, or have not been set to a valid entry.

Calin Negru28-Apr-20 1:16

28-Apr-20 1:16

Just to clarify over on pointer/array as argument

One way is to pass the array as pointer

C++

int Function( int * arrayargument)
{
for(int i =0; i < 10; i++)
{
 arrayargument[i] = 1;
}

}

int AnArray[10];
//case1
Function(AnArray);
//case2
Function(&AnArray[0]);

could same result be achieved by calling it case2 mode?

Richard MacCutchan28-Apr-20 2:40

28-Apr-20 2:40

Yes, in case 1 the compiler assumes the name of the array actually means a pointer to the first element. In case 2 you have specifically requested "pass the address of the first element of the array".

Calin Negru28-Apr-20 3:08

28-Apr-20 3:08

Thanks
When you can do the same thing in several ways something is not right Smile | :)

k505428-Apr-20 3:23

k5054

28-Apr-20 3:23

fearless_ wrote:
When you can do the same thing in several ways something is not right

I can only imagine the following program will blow your mind:

C++

#include <stdio.h>

int main()
{
    int a[] = { 0, 1, 2, 3, 4, 5, 6, 7};
    int i1 = a[2];
    int i2 = 2[a];

    printf("i1 = %d  i2 = %d\n", i1, i2);

    return 0;
}

Keep Calm and Carry On

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Greg Utas28-Apr-20 2:48

Greg Utas

28-Apr-20 2:48

I would also pass the size of the array to the function instead of hard-coding it at 10:

int Function(int* arrayargument, size_t size)

Calin Negru28-Apr-20 3:36

28-Apr-20 3:36

I was trying to keep the example as simple as possible. But since we`re here, what`s size_t? It`s the second time I see someone using it, is it an actual variable or just a custom?

modified 28-Apr-20 11:04am.

Victor Nijegorodov28-Apr-20 8:49

Victor Nijegorodov

28-Apr-20 8:49

size_t is just a type. Like int, long, and so on

Calin Negru28-Apr-20 9:54

28-Apr-20 9:54

Thanks Victor

you mean a built-in type in a c++ compiler? what makes it particular, with float the compiler will let you use the comma, char is a like a tiny int, what makes size_t special?

modified 28-Apr-20 16:22pm.