C / C++ / MFC

Rich edit control and caption

15-Dec-13 2:59

An easy mistake, but most programmers I know have made it a few times in their lives. Using constants to set the values helps to avoid issues such as this, for example:

C++

static const int ROWS = 4;
static const int COLUMNS = 5;

BITMAP *buffer;
class Bricks {
      
         public:
                  int bricks_array[ROWS][COLUMNS];
                  void display_Bricks();
                  int fill_bricks();
};
 
int Bricks::fill_bricks()
{
         for(int i = 0; i < ROWS; i++)//layer
         {
                     for(int j = 0; j < COLUMNS; j++)//brick_no 
// ...

Veni, vidi, abiit domum

RaymondM14-Dec-13 1:43

RaymondM

14-Dec-13 1:43

I have a window created with CreateWindowEx, with a caption. When I load the text using EM_STREAMIN the opening line of the text goes into the caption, replacing the intended title. How do I prevent this, so as to retain the intended caption ?

Re: Rich edit control and caption

Richard MacCutchan15-Dec-13 0:34

Re: Rich edit control and caption

15-Dec-13 0:34

You need to show us the code that causes this to happen.

Veni, vidi, abiit domum

enhzflep15-Dec-13 3:56

enhzflep

15-Dec-13 3:56

What exactly do you mean by "with a caption". RichEdits are the same as a 'standard' edit, in that they don't have a caption. They simply contain text that may be edited by the user. In the case o a RichEdit, formatting and OLE objects are supported too. But captions? Nah, not according to any of the dozens of documents I've ever read on the matter. I've added captions to them, but that's through additional code - not through any inherent functionality of their own.

Any caption that you have is a result of code that you have that we can't see. If you'd like a solution to your problem, you'll have to show us how you got into the predicament in the first place. Or as Richard said, you'll need to show code to get an answer.

NON MFC / WINAPI Problem related to Process and Files.

lokesh.mavale13-Dec-13 13:07

lokesh.mavale

13-Dec-13 13:07

how to Generate list of processes which are accessing file /FOLDER/ Directory ??
.
as exactly "UNLOCKER" works!!
is there any function available in WINAPI for this?

Extract RGB Colors

Django_Untaken13-Dec-13 1:31

Django_Untaken

13-Dec-13 1:31

Hello. How do I extract RGB colors from a byte ? Thanks

Re: Extract RGB Colors

Richard MacCutchan13-Dec-13 1:49

C pointer and array question [Resolved]

13-Dec-13 1:49

See http://msdn.microsoft.com/en-us/library/windows/desktop/ms536244(v=vs.85).aspx[^].

Veni, vidi, abiit domum

Re: Extract RGB Colors

CPallini13-Dec-13 3:06

CPallini

13-Dec-13 3:06

If you have 1 byte representing a color then it is probably just the index of the full RGB color inside the corresponding palette.

Veni, vidi, vici.

Re: Extract RGB Colors

Eugen Podsypalnikov13-Dec-13 3:18

Eugen Podsypalnikov

13-Dec-13 3:18

Just mask the bits[^] out Smile | :)

(do you still need some help ?)

They sought it with thimbles, they sought it with care;
They pursued it with forks and hope;
They threatened its life with a railway-share;
They charmed it with smiles and soap. Smile | :)

econy12-Dec-13 20:07

econy

12-Dec-13 20:07

I want to use a pointer to get an array elements value.

C++

char s1 = {1,2,3,4,5,6,7};
int t1 = *(int*)(&s1[2]);

I think t1 value is 3456,but in fact, it returns a strange value looks like an address value.

But I make a struct type like:

C++

struct TestStruct {
	char c1;
	char c2;
	char c3;
        char c4;
}ts1;

ts1 = *(TestSTruct*)(&s1[2]);

then I can get ts1.c1 = 3, ts1.c2 = 4, ts1.c3 = 5,..

Can anybody give me some hint?

modified 13-Dec-13 2:19am.

Re: C pointer and array question

econy12-Dec-13 20:19

econy

12-Dec-13 20:19

Resolved

Richard MacCutchan12-Dec-13 21:19

12-Dec-13 21:19

In both cases your syntax seems to be somewhat confused. For case 1 why not just:

C++

char s1[] = {1,2,3,4,5,6,7};
int t1 = s1[2];

In case 2, you are casting an array to a structure which will in many cases break your code. Structures will often have their elements aligned on word boundaries so what you think is elemnt n of the array is actually something completely different. If you want to use a structure then fill it with your data in the first place. Don't use casts unless you know that the data will be in the locations you think it will.

[edit]
Added [] after s1, as Stefan pointed out.
[/edit]

Veni, vidi, abiit domum

modified 13-Dec-13 5:00am.

Stefan_Lang12-Dec-13 22:42

Stefan_Lang

12-Dec-13 22:42

shouldn't this be

C++

char* s1 = {...};

rather than

C++

char s1 = {...};

?

The latter is just a single char, and using s1 as an array will lead to invalid memory references; most likely such attempts will access arbitrary adresses on the stack (i. e. other stack variables or parts of them).

GOTOs are a bit like wire coat hangers: they tend to breed in the darkness, such that where there once were few, eventually there are many, and the program's architecture collapses beneath them. (Fran Poretto)

econy16-Dec-13 9:14

econy

16-Dec-13 9:14

Forgot to indicate, s1 is a global array.

In fact, I tested, the method works, the weird value is because I use %d to print, when i change %d to %x, it prints correct result

Stefan_Lang16-Dec-13 21:25

Stefan_Lang

16-Dec-13 21:25

My point was that the code you posted produces a compiler error in line 1. I suggested you should correct it in your posting so we can see what you your code really looks like, rather than guessing what it might be.

The difference between %d and %x is that the former expects a signed integer variable and prints it as such, whereas the latter will completely ignore the type of the variable and print whatever it finds in unsigned hexadecimal. In general, I doubt that is what you wanted, although for values lower than 10 it may look like it. If %d produces a different output than %x for a variable of type char, then the only relevant difference is signed/unsigned, so %ud shoud print the same as %x.

Replacement for Inline Assembly

Stefan_Lang12-Dec-13 23:14

Stefan_Lang

12-Dec-13 23:14

econy wrote:
then I can get ts1.c1 = 3, ts1.c2 = 4, ts1.c3 = 5,..

Note that there is no guarantee the compiler will lay out struct members in the exact same order you defined them.

econy wrote:
ts1 = *(TestSTruct*)(&s1[2]);

There is no guarantee this will work as expected with any modern compiler, especially if that struct contains more than just four chars. The compiler may have to modify the total memory layout depending on padding, virtual function table, base classes, and debug information (and possibly for other reasons, too).

If you want a clean solution, just provide a simple constructor and maybe assignment operator:

C++

struct TestStruct {
   TestStruct(const char c1_, const char c2_, const char c3_, const char c4_)
    : c1(c1_), c2(c2_), c3(c3_), c4(c4_)
   {
   }
   TestStruct(const char* s)
   {
      operator=(*s);
   }
   TestStruct* operator=(const char* s)
   {
      if (s != nullptr)
      {
         c1 = c1_;
         c2 = c2_;
         c3 = c3_;
         c4 = c4_;
      }
      return *this;
   }

   ...
};

You can then initialize your structs in any of the following ways:

C++

const char* s1 = {1, 2, 3, 4, 5, 6, 7};
struct TestStruct ts1(3, 4, 5, 6);
struct TestStruct ts2(s1+2);
struct TestStruct ts3;
ts3 = s1+2;

Please note that this last assignment may lead to unintentional errors if used carelessly. but at least it's readable and extendable.

[edit]
Sorry, I just noted that you asked about C, not C++. For C, most of my concerns expressed above don't apply! Your assignment statement is essentially correct in that case (although you could simplify &s1[2] to s1+2 if you want to)
[/edit]

modified 13-Dec-13 5:46am.

Richard Andrew x6412-Dec-13 18:08

Richard Andrew x64

12-Dec-13 18:08

Since 64-bit C++ code does not allow inline assembly instructions, how can I execute a jmp instruction when I need to?

The difficult we do right away...
...the impossible takes slightly longer.

Richard MacCutchan12-Dec-13 21:05

12-Dec-13 21:05

Why would you need to?

Veni, vidi, abiit domum

Richard Andrew x6413-Dec-13 7:44

Richard Andrew x64

13-Dec-13 7:44

Richard MacCutchan wrote:
Why would you need to?

I want to transfer control to a different function without disturbing the stack. (Without pushing anything more onto it.

The difficult we do right away...
...the impossible takes slightly longer.

Rajesh R Subramanian12-Dec-13 23:31

Rajesh R Subramanian

12-Dec-13 23:31

Compiler intrinsics[^]?

"Real men drive manual transmission" - Rajesh.

Eugen Podsypalnikov13-Dec-13 1:14

Eugen Podsypalnikov

13-Dec-13 1:14

// how can I execute a jmp instruction when I need to?

1. Organize a buffer for the JMP executing

C++

  enum {
#ifndef _WIN64
    jmpAddrIdx  = 2,  // Index of the Address in Jump-Buffer
    jmpLen      = 10, // Length of the Jump-Buffer
#else
    jmpAddrIdx  = 3,  // Index of the Address in Jump-Buffer
    jmpLen      = 16, // Length of the Jump-Buffer
#endif
  };
      static BYTE jmp[jmpLen] = {
#ifdef _WIN64
        0x50,                                           // push rax           (len:01)
        0x48, 0xb8,                                     // mov rax, DWORD_PTR (len:10)
        0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
        0x48, 0x87, 0x04, 0x24,                         // xchg rax, [rsp]    (len:04)
        0xc3                                            // ret                (len:01)
#else
        0x50,                                           // push eax           (len:01)
        0xb8,                                           // mov eax, DWORD_PTR (len:05)
        0x00, 0x00, 0x00, 0x00,
        0x87, 0x04, 0x24,                               // xchg eax, [esp]    (len:03)
        0xc3                                            // ret                (len:01)
#endif
      };

2. Fill the address part there in (low Bytes first)

C++

memcpy(&jmp[jmpAddrIdx], YOUR_DESIRED_ADDRESS, sizeof(DWORD_PTR));

3. Take the pointer of an existing global function(void) (Long enough: see jmpLen above)
4. Mark the addressed space of the function as writeable

C++

DWORD dwOldMode(0);
if (VirtualProtect(pfnYourShellFcn, jmpLen, PAGE_EXECUTE_READWRITE, &dwOldMode)) {

5. Write the jump into the function Smile | :)

C++

memcpy(pfnOriginal, jmp, jmpLen);

6. Mark the space as original

C++

VirtualProtect(pfnYourShellFcn, jmpLen, dwOldMode, &dwOldMode);

7. Call the pointed function Smile | :)

C++

(*pfnYourShellFcn)()

8. Be thrilled.

They sought it with thimbles, they sought it with care;
They pursued it with forks and hope;
They threatened its life with a railway-share;
They charmed it with smiles and soap. Smile | :)

modified 13-Dec-13 7:25am.