Re: error C2678 - C / C++ / MFC Discussion Boards

Re: error C2678

_Flaviu6-Oct-19 7:26

_Flaviu

6-Oct-19 7:26

So the finest solution is to take these values from enum and put them as #defines. I will do this change.

Re: error C2678

_Flaviu6-Oct-19 10:04

_Flaviu

6-Oct-19 10:04

I am afraid that I cannot change that enum into #defines, because I have:

C++

na->flags |= flag;

where

C++

FILE_FLAGS flag;

and
na is struct level1, and inside this level1 struct, I have

C++

struct level1
{
FILE_FLAGS flags;
....
};

I have entered in some deadlock ? Please help me to solve this error ...

Re: error C2678

Victor Nijegorodov6-Oct-19 20:34

Victor Nijegorodov

6-Oct-19 20:34

Try to declare both flags and flag as int

Re: error C2678

_Flaviu6-Oct-19 21:30

_Flaviu

6-Oct-19 21:30

Yes, but FILE_FLAGS is enum with int values ...

Re: error C2678

Victor Nijegorodov6-Oct-19 21:43

Victor Nijegorodov

6-Oct-19 21:43

Then, as Richard already suggested replace this enum with a set of #define.

Re: error C2678

_Flaviu6-Oct-19 21:58

_Flaviu

6-Oct-19 21:58

Agree, but that enum is a part of another struct ... so, how can I put as part of a struct several #defines ?

Re: error C2678

Richard MacCutchan6-Oct-19 22:22

Richard MacCutchan

6-Oct-19 22:22

Of course you can change it to #defines. The definition of FILE_FLAGS then becomes an int type. And then the rest of the code should compile correctly.

Re: error C2678

_Flaviu7-Oct-19 9:16

_Flaviu

7-Oct-19 9:16

I am not get something, so forgive me.

I have moved those enum values as #defines, but of course, now I get error from struct: doesn't know who is FILE_FLAGS flags; from level1 struct.

C++

/*
typedef enum {
	FILE_READONLY = 0x00000001,
	FILE_HIDDEN = 0x00000002,
	FILE_SYSTEM = 0x00000004,

	FILE_DIRECTORY = 0x00000010,
	FILE_ARCHIVE = 0x00000020,
	FILE_DEVICE = 0x00000040,
	FILE_NORMAL = 0x00000080,

	FILE_TEMPORARY = 0x00000100,
....
.....

}FILE_FLAGS;
*/

#define	FILE_READONLY = 0x00000001
#define	FILE_HIDDEN = 0x00000002
#define	FILE_SYSTEM = 0x00000004

of course, FILE_FLAGS enum has disappeared ... obviously, I don't understood something ... but what ?

C++

struct level1
{
FILE_FLAGS flags; // <-- error
....
};

Re: error C2678

Victor Nijegorodov7-Oct-19 9:24

Victor Nijegorodov

7-Oct-19 9:24

_Flaviu wrote:
struct level1
{
FILE_FLAGS flags; // <-- error
....
};

Try

C++

struct level1
{
   int flags; // <-- error
   ....
};

Re: error C2678

_Flaviu7-Oct-19 20:21

_Flaviu

7-Oct-19 20:21

Ok, but even flag is comming as function parameter, just like this:

C++

static void SomeFunction(level1* na, FILE_FLAGS flag)
{
....
	na->flags |= ~flag;
....	
}

So, I guess I cannot give up FILE_FLAGS enum ... don't I ?

Re: error C2678

Victor Nijegorodov7-Oct-19 20:39

Victor Nijegorodov

7-Oct-19 20:39

Change this parameter to be

C++

static void SomeFunction(level1* na, int flag)
{

Re: error C2678

Richard MacCutchan7-Oct-19 21:55

Richard MacCutchan

7-Oct-19 21:55

Add this line somewhere before the first reference to FILE_FLAGS :

C++

typedef int FILE_FLAGS;

Re: error C2678

_Flaviu7-Oct-19 23:24

_Flaviu

7-Oct-19 23:24

I encounter another error if I made these modifications:

C++

data->com = na->flags & ATTR_IS_COMPRESSED; // <-- error C2059: syntax error : '='

(where data->com is int)
because now ATTR_IS_COMPRESSED is #define, not part of enum FILE_FLAGS ...

modified 8-Oct-19 5:37am.

Re: error C2678

Richard MacCutchan7-Oct-19 23:33

Richard MacCutchan

7-Oct-19 23:33

What is data->com?

_Flaviu wrote:
because now ATTR_IS_COMPRESSED is #define, not part of enum FILE_FLAGS

That is not the reason. I can only assume that you have done a partial change and some parts of your code are still incorrect. If you still have the FILE_FLAGS enum then it is going to cause problems.

It would probably help if you showed all the code portions that are connected. It is difficult to be certain of the answers when looking at only a single line of code.

Re: error C2678

Richard MacCutchan8-Oct-19 1:11

Richard MacCutchan

8-Oct-19 1:11

I still cannot see enough information. Please provide what I previously requested and reply to this message. Please do not email me personally.

Re: error C2678

_Flaviu8-Oct-19 1:41

_Flaviu

8-Oct-19 1:41

I only said that I updated the previous post. Ok, I will come with new informations.

Re: error C2678

_Flaviu8-Oct-19 4:12

_Flaviu

8-Oct-19 4:12

The fact is like that: I have an error:

C++

error C2059: syntax error : '='

the error is reported here:

C++

data->com = na->flags & ATTR_IS_COMPRESSED;

where:
data is a struct:

C++

struct data
{
.....
	int		 com;
...
};

and na is

C++

RECORD* na;

and RECORD is:

C++

typedef struct {
....
....
		int flags;
.....		
}RECORD;

and

ATTR_IS_COMPRESSED

is from here (from my modifications):

C++

typedef int ATTR_FLAGS;

//typedef enum {
//	ATTR_IS_COMPRESSED = 0x0001,
//	ATTR_COMPRESSION_MASK = 0x00ff,
//}ATTR_FLAGS;

#define ATTR_IS_COMPRESSED = 0x0001
#define ATTR_COMPRESSION_MASK = 0x00ff

Re: error C2678

Richard MacCutchan8-Oct-19 5:12

Richard MacCutchan

8-Oct-19 5:12

Not sure why you posted all that back to front ...

However there are a couple of simple mistakes:

#define statements do not require an = sign. They should be

C++

#define ATTR_IS_COMPRESSED 0x0001
#define ATTR_COMPRESSION_MASK 0x00ff

The name data refers to a struct definition, not a variable. You need something like:

C++

typedef struct
{
.....
	int		 com;
...
} DATA;

DATA* data;

I am assuming that you actually assign the memory required for both structures at some point further on.

Re: error C2678

_Flaviu8-Oct-19 5:25

_Flaviu

8-Oct-19 5:25

That was the problem, on #define: I assigned with '='. My bad !

unary minus operator applied to unsigned type, result still unsigned

_Flaviu3-Oct-19 23:07

_Flaviu

3-Oct-19 23:07

This warning from post title is more an information than a warning: unary minus operator applied to unsigned type, result still unsigned
but is signaled here:

C++

static unsigned char buffer[512];
static long long var = -sizeof(buffer) - 1; // <-- warning C4146: unary minus operator applied to unsigned type, result still unsigned

Still, how can I rid of this warning ?

Re: unary minus operator applied to unsigned type, result still unsigned

phil.o3-Oct-19 23:50

phil.o

3-Oct-19 23:50

You can cast the result of the sizeof call to a long long prior to apply it the unary minus operator:

C++

static long long var = -((long long)sizeof(buffer)) - 1;

It makes sense when you think of what should the result be when you try to negate a value of a type which does not accept negative values.

"Five fruits and vegetables a day? What a joke!
Personally, after the third watermelon, I'm full."

Re: unary minus operator applied to unsigned type, result still unsigned

_Flaviu4-Oct-19 0:57

_Flaviu

4-Oct-19 0:57

Thanks. That warning has disappeared.

modified 4-Oct-19 10:19am.

OnInitDialog() MFC vc++

Member 145755563-Oct-19 19:32

Member 14575556

3-Oct-19 19:32

I have created a ComboBox with drop down using the wizard and added three data(First,Second and Third) through properties. So what I didn't understand is that in the MyDlg::OnInitDialog() when I commented the base OnInitDialog() the data in the drop down doesn't show up, why?. I know that the base OnInitDialog() call UpdateData(), but even if I keep UpdateData(FALSE) below it, it didn't work.
Could you please help me clear my doubt. Thanks in advance. Smile | :)

C++

BOOL MyDlg::OnInitDialog() {
	CDialogEx::OnInitDialog(); // <----- when I comment this line the data in the drop down is not showing


	UpdateData(FALSE);
	return TRUE;
}

Re: OnInitDialog() MFC vc++

Richard MacCutchan3-Oct-19 20:58

Richard MacCutchan

3-Oct-19 20:58

You nee to call the base version to complete proper initialisation. Always refer to the documentation for the MFC classes to ensure you are following the rules.

How should I manage my register addresses and expose some of them properly and ensure consistency?

arnold_w3-Oct-19 8:00

arnold_w

3-Oct-19 8:00

My product has registers that are accessed via addresses:

C++

#define MY_REG_0            ((uint32_t)0)
#define MY_REG_1            ((uint32_t)1)
#define MY_REG_2            ((uint32_t)2)

Some of these registers (but not all!) need to be shared with another product and I have put them in a common git submodule:

C++

#define MY_PRODUCT_MY_REG_1            ((uint32_t)1)

Is this the recommended way to do it? I would like to have a macro

C++

CHECK_ADDR_MACRO(MY_REG_1, MY_PRODUCT_MY_REG_1);

that generates static_assert compile time error if:
a) MY_REG_1 and MY_PRODUCT_MY_REG_1 are not equal.
b) Neither MY_REG_1 or MY_PRODUCT_MY_REG_1 are defined (the register was removed, but someone forgot to remove the check.

Can someone please recommend a way to implement the macro CHECK_ADDR_MACRO?

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