Re: Storing 2 longs in a single variable - C / C++ / MFC Discussion Boards

Re: Storing 2 longs in a single variable

Gilfrog1-Oct-02 7:02

Gilfrog

1-Oct-02 7:02

How do i get the two longs back out of the unsigned__int64?

Re: Storing 2 longs in a single variable

C^hris L^osinger1-Oct-02 10:56

C^hris L^osinger

1-Oct-02 10:56

longOne = i64 / (unsigned long)-1;
longTwo = i64 - (longOne * (unsigned long)-1);

or something similar

-c

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Re: Storing 2 longs in a single variable

Tomasz Sowinski1-Oct-02 6:57

Tomasz Sowinski

1-Oct-02 6:57

Gilfrog wrote:
I need it to be in one variable.

You may use __int64 if you want to play with shifting bits. But why can't you use a structure?

Tomasz Sowinski -- http://www.shooltz.com

*** Si fractum non sit, noli id reficere. ***

Re: Storing 2 longs in a single variable

Ryan B.1-Oct-02 7:52

Ryan B.

1-Oct-02 7:52

A structure would solve the issue would it not?

#pragma pack(1)
typedef struct two_longs_dont_make_a_right
{
long one;
long erone;
} two_longs;

? Why in 'one' variable?

Ryan Baillargeon
Software Specialist
Fuel Cell Technologies Inc.

Re: Storing 2 longs in a single variable

Anonymous1-Oct-02 8:26

Anonymous

1-Oct-02 8:26

I need to save an Array of 2 shorts and long to a text file. I just figured it would be easier to save them in one variable that to seperate them with commas or something like that.

Re: Storing 2 longs in a single variable

Chris Richardson1-Oct-02 8:33

Chris Richardson

1-Oct-02 8:33

Why not use a structure in combination with a union, like so:

typedef struct tagTwoLongs
{
   union
   {
      struct
      {
         long Long1;
         long Long2;
      };
      __int64 OneVariable;
   };
}TwoLongs;

Now you can refer to the two longs separately, via Long1 and Long2, or together, via OneVariable.

Chris Richardson

Re: Storing 2 longs in a single variable

Scott H. Settlemier1-Oct-02 9:19

Scott H. Settlemier

1-Oct-02 9:19

Make sure that the pack pragma is 4 or less for the union
technique to work. You might want to ensure this by temporarily
specifying the packing alignment:

<br />
#pragma pack(push,4)<br />
typedef struct tagTwoLongs<br />
{<br />
   union<br />
   {<br />
      struct<br />
      {<br />
         long Long1;<br />
         long Long2;<br />
      };<br />
      __int64 OneVariable;<br />
   };<br />
}TwoLongs;<br />
#pragma pack(pop)

P.S. Is there a way to get a compile time
assertion that sizeof(long)==4?

Re: Storing 2 longs in a single variable

Chris Richardson1-Oct-02 9:22

Chris Richardson

1-Oct-02 9:22

Good call on the packing. I forgot about that.

Scott H. Settlemier wrote:
P.S. Is there a way to get a compile time
assertion that sizeof(long)==4?

Yeah, in winnt.h, there's a macro called C_ASSERT. Here's it's definition, and the comment that describes it:

//
// C_ASSERT() can be used to perform many compile-time assertions:
//            type sizes, field offsets, etc.
//
// An assertion failure results in error C2118: negative subscript.
//

#define C_ASSERT(e) typedef char __C_ASSERT__[(e)?1:-1]

Chris Richardson

Re: Storing 2 longs in a single variable

Scott H. Settlemier1-Oct-02 9:38

Scott H. Settlemier

1-Oct-02 9:38

ooh, nice. thanks. I've been wanting that ability
for a long time. I see they just sorta kludged
one up there. (neg index error. Laugh | :laugh:

)

Too bad this wasn't added to the language.

Re: Storing 2 longs in a single variable

Gilfrog1-Oct-02 10:00

Gilfrog

1-Oct-02 10:00

thanks, that works for me.

Re: Storing 2 longs in a single variable

PJ Arends1-Oct-02 10:24

PJ Arends

1-Oct-02 10:24

You mean the Win32 LARGE_INTEGER structure defined in WinNT.h

CPUA 0x5041

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Re: Storing 2 longs in a single variable

Chris Richardson1-Oct-02 10:32

Chris Richardson

1-Oct-02 10:32

I only replied to him an idea and a simple definition. I suppose I could have used (and would have used) LARGE_INTEGER as my example, but I didn't think of it at the time.

Chris Richardson

DataStorage / Modification Project

Anonymous1-Oct-02 6:20

Anonymous

1-Oct-02 6:20

I need a sample project - how to handle with data (store/edit/delete) in any format - but without any additional actions (registering in ODBC, etc.) I want to have redistributable application, wich are need juct unpack, and have to work with data.

thank tou.

VS6 and VS7(.NET)

ns1-Oct-02 6:17

1-Oct-02 6:17

Can I put both of these on the same machine? Any known problems or conflicts?

thanks
ns

Re: VS6 and VS7(.NET)

Jeremy Falcon1-Oct-02 6:55

Jeremy Falcon

1-Oct-02 6:55

There have been a couple people here on CP that seems to be running both concurrently with no problems. I haven't tried it myself though.

Jeremy Falcon
Imputek

<nobr>"Oh no there was a knife in that kitchen drawer and I cut myself - please remove the kitchen." - David Wulff

Re: VS6 and VS7(.NET)

ns1-Oct-02 6:58

1-Oct-02 6:58

Thank you. I just called MS and they said theres no problem....so I shall be brave and give it a try. Smile | :)

Appreciate your help,
ns

Re: VS6 and VS7(.NET)

Mariusz Popiolek1-Oct-02 7:01

Mariusz Popiolek

1-Oct-02 7:01

Rather yes. I'm using both IDEs for few months and everything works fine. I think that it will be better if you install VS6 before VS7.

greetings

Re: VS6 and VS7(.NET)

ns1-Oct-02 7:00

1-Oct-02 7:00

Great! Now if I click on a vS6 dsw, what program will be launched? VS6? Or do I have to first start VS6, then load the VS6 project into it?

Appreciate your help,
ns

Re: VS6 and VS7(.NET)

Mariusz Popiolek1-Oct-02 7:28

Mariusz Popiolek

1-Oct-02 7:28

If you have installed VS6 before VS7 dsw file type (and of course all files connected with VS) will be connected with VS7, therefore VS7 will be launched, so you will have to load project manually in VS6.

greetings

Re: VS6 and VS7(.NET)

ns1-Oct-02 7:28

1-Oct-02 7:28

Okay. makes eminent sense. Thanks

Appreciate your help,
ns

Exporting & using static public data members between dlls

mabotta1-Oct-02 6:14

mabotta

1-Oct-02 6:14

Hi,
I have a VC++ project;

I have a dll with several classes that I export (one of them is this one, with static members declared in a header file and initialized in it’s .cpp file), and I’m using them from another dll. For the other classes I had no troubles (I included the header files and used them normally) but I don’t know what happens with this one.

When I see the dll’s depends it’s all ok; I can see the class and its attributes, but when I try to use it from another dll (like className::attributeName ), at linking time, I got an ‘unresolved external symbol’ error, but it compiles well.

I’ve tried:
- Include the class header file with __declspec(dllimport) in the dll that uses it
At linking time returns ‘error LNK2001: unresolved external symbol’

- Make a header file with extern sentence ( extern string className::attributeName; );
At compiling time returns: file.h(53) : error C2720: [attributeName] : 'extern ' storage-class specifier illegal on members

- The same header file, but with extern “C” sentence
( extern “C” string className::attributeName )
At linking time return:
file.obj : warning LNK4006: "public: static class string className::attributeName already defined in file2.obj; second definition ignored

Can someone help me to resolve this?
Thanks

Paranoico? yo???

Re: Exporting & using static public data members between dlls

Tomasz Sowinski1-Oct-02 6:27

Tomasz Sowinski

1-Oct-02 6:27

It should work - it does for me. I guess your second dll (the one which should import) is having problems with correct __declspec. Can you create small exe which links dynamically with dll exporting static members?

Tomasz Sowinski -- http://www.shooltz.com

*** Si fractum non sit, noli id reficere. ***

Re: Exporting & using static public data members between dlls

mabotta1-Oct-02 7:53

mabotta

1-Oct-02 7:53

It was a good idea, but It returned the same errors.
Frown | :(

Paranoico? yo???

Another checkbox question....

ns1-Oct-02 5:59

1-Oct-02 5:59

Now that it checks(thanks Smile | :)

), I am doing:

    UpdateData(FALSE);

if(m_checkDont.GetState() & 0x0003 == 1)
{
    value = xDont;
}

I check the box , and the press the button which runs the above snipppet> But my code skips the if. I got the mask test out of MSDN.
(If its checked, I want to set value)

Appreciate your help,
ns

Re: Another checkbox question....

Tomasz Sowinski1-Oct-02 6:02

Tomasz Sowinski

1-Oct-02 6:02

Why don't you use CButton::GetCheck instead?

(if you insist on messing with GetState, use '!= 0' instead of '== 1')

Tomasz Sowinski -- http://www.shooltz.com

*** Si fractum non sit, noli id reficere. ***

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