Problem with GetProcAddress - C / C++ / MFC Discussion Boards

earl3-Jul-06 17:54

3-Jul-06 17:54

Are you sure you're sending stuff OK? No problems with a crlf /cr / lf terminator being incorrect on your end?

earl

-- modified at 23:54 Monday 3rd July, 2006

PS: depending on how you're sending this, (just OpenFile on the port?) make sure to flush your buffer so that the packet is guaranteed sent...

Re: serial communication

Rilhas9-Jul-06 5:19

Rilhas

9-Jul-06 5:19

The problem could have hundreds of explanations, since the probable complexity of your hardware and software setup are much higher than the degree of detail you provided.

However, I would sugest you try out the most basic things. One thing that usually happens is cross talk between TX and RX cables resulting in the PC receiving the same bytes it sends. For example, you send a byte and as the bits are sent through the TX the RX cable picks them up (due to cable cross talk) and interprets them as being received from the remote end. All the bits will be valid, including start and stop bits, so the serial port just reads them in at the same time.

Of course, this could also apply to the microcontroller. This could lead to symptoms as you describe if your protocol uses similar bytes to allow confusion between cross talk and repetition.

I hope this helps.

Rilhas

StdAfx questions

Super Lloyd3-Jul-06 17:04

Super Lloyd

3-Jul-06 17:04

I have problem on how to use StdAfx & precompiled headers.
Apparently it's an extremely important header and everything I write before
#include "stdafx.h" is ignored.. Frown | :(

(tooks me awhile to figure that error!)

anyway apparently precompiled header could slow down your compilation a lot (instead of speeding it up) if they are regenerated too often.

the problem is I have no idea when they are regenerated.. Sigh | :sigh:

so here is my question:

1. is it okay to #include "stdafx" in my header (by default its' only included in the .cpp)

2. is it okay to include it after the "guarding define", that is after
#ifndef __SOMCONST___
#define __SOMCONST___
#include "stdafx.h"

....

#endif

3. is it ok to write into include for common system headers + seldom changing projet #define

any other tips wellcome Wink | ;)

Re: StdAfx questions

Michael Dunn3-Jul-06 17:10

Michael Dunn

3-Jul-06 17:10

You should include stdafx.h in every .cpp file, not in any header files. If you do that, the header guards will prevent all the stdafx.h contents from being parsed again, but it'll look sloppy.

--Mike--
Visual C++ MVP Cool | :cool:

LINKS~! Ericahist | PimpFish | CP SearchBar v3.0 | C++ Forum FAQ

VB > soccer

Re: StdAfx questions

Super Lloyd3-Jul-06 18:32

Super Lloyd

3-Jul-06 18:32

thanks.

although I was asking a question on what really happen more than best practice Unsure | :~

Re: StdAfx questions

Saurabh.Garg3-Jul-06 20:58

Saurabh.Garg

3-Jul-06 20:58

have a look at this article[^].

-Saurabh

Re: StdAfx questions

Super Lloyd3-Jul-06 21:07

Super Lloyd

3-Jul-06 21:07

Excellent!
Thanks! Big Grin | :-D

Problem with GetProcAddress

RedDragon2k3-Jul-06 16:39

RedDragon2k

3-Jul-06 16:39

Hey Guys,

I got a piece of Unix Code but I have to make it run under Windows. Unfortunately I contains the function mmap (a Unix Function). Fortunately there is this nice DLL called cygwin1.dll which gives you some Unix Functions.

<br />
    HINSTANCE hDll = LoadLibrary("cygwin1.dll");<br />
    if(hDll)<br />
    {<br />
            printf("DLL Loaded !\r\n");<br />
            FARPROC mmap = GetProcAddress(hDll,"mmap");<br />
            if(mmap)<br />
            {<br />
                    printf("Function found !\r\n");<br />
                    mydata= mmap(mydata, myLength,PROT_READ,MAP_PRIVATE,fd,0);<br />
            }<br />
            else<br />
            {<br />
                    printf("Function not found!\r\n");<br />
            }<br />
    }<br />
    else<br />
    {<br />
            printf("Failed to load DLL!\r\n");<br />
    }<br />

This is the code I use. But when I then try to call the mmap function my compiler tells me that I'm passing to many arguments to mmap. WTF | :WTF:

Normally I don't load libraries at runtime. So please help me Sigh | :sigh:

Re: Problem with GetProcAddress

earl3-Jul-06 17:52

earl

3-Jul-06 17:52

Hey,

You're getting a function pointer back, but GetProcAddress can't possibly know what the function definition of mmap is so you have to tell it.

Assuming that you are using the results from "man mmap"

#include      < sys/mman.h >

void*  mmap(void *start, size_t length, int prot, int flags, int fd, off_t offset);

then you would do something like this

#include < windows.h >

typedef void* (CALLBACK* PFNMMAP)(void*, size_t, int, int, int, off_t);


//blah -- open the DLL, etc

PFNMMAP pmmap;

if( (pmmap = GetProcAddress(dllHandle, "mmap"))) {


   //do something here


}

now pmmap is a function pointer with the right signature -- ie of type PFNMMAP. Oh yes, modify CALLBACK based on the way the dll export table was declared (it should work for __declexport).

Also, there are two types of libs on windows. One, called a .lib, is code made to be statically linked into a file. The other, for your convenience also called a .lib, is code that is statically linked at compile time but just thunks to a dll. The latter is often more convenient as it will handle the LoadLibrary and GetProcAddress stuff for you.

The downside to using import libs is that windows tries to load the dll before your main / WinMain is called. If it can't find the dll you never get control. At least with manual LoadLibrary calls you can be intelligent about telling the user just what you can't find and what he or she ought to do about it.

PS: I don't have a compiler on this computer so I can't promise any of this works.

HTH

earl

Re: Problem with GetProcAddress

Hamid_RT3-Jul-06 20:21

Hamid_RT

3-Jul-06 20:21

How many parameter in this function mmap and use mmap with correct parameter

whitesky

newfile , new window in MDI

zeus_master3-Jul-06 15:59

zeus_master

3-Jul-06 15:59

what's the difference between file->new and window->newwindow in MDI project(pj name mydoc)?

why use file->new, the newfile name is mydoc1(or mydoc2,mydoc3,mydoc4.......)
but window->new Window, the new doc name is mydoc1:2 (or mydoc1:3, mydoc1:4, mydoc2:2.......)?

Re: newfile , new window in MDI

zeus_master3-Jul-06 18:35

zeus_master

3-Jul-06 18:35

hi,I need your help......

Re: newfile , new window in MDI [modified]

*Dreamz3-Jul-06 20:08

*Dreamz

3-Jul-06 20:08

File -> New
New Document
New View

Window -> New
Same Document
New View

c++ and external structs [modified]

earl3-Jul-06 14:25

earl

3-Jul-06 14:25

So, here's the issue:

//******globals.h

#ifndef ___GLOBALS_H___
#define ___GLOBALS_H___
//the aspect ratio
enum AspectRatio {
	Aspect4to3,
	Aspect5to3,
	Aspect5to4,
	AspectOther
};

/* the global state struct; throw all globals in here */
struct GState	
{
	bool isDebugMode;
	//align: char a,b,c; //unsigned int a:24;				//align
	AspectRatio aspectRatio;
	unsigned int canary;
};

extern struct SState gState;

#endif

and for the declaration:

//***** globals.cpp
#include"globals.h"

SState gState;

Now, the problem: this is being compiled with VC6SP5 (yes, I know, there's nothing I can do for the time being). I manually checked that all files are being compiled with the same flags. In most files, I include globals.h and everything is kosher. In *some* files, the address of aspectRatio is bumped by 3. I can't figure out what this could possibly be except some weird alignment issue.

Solutions: if I uncomment char a,b,c;, then everything works. If I put unnamed (or named) bitfields in, either unsigned int : 0 or unsigned int:24 (the former promises to align everything that follows on an int), it's still broken.

So, for example, in one file,

printf("isDebugMode = %u, address = %X \naspect ratio = %u, address = %X \n"
       "canary=%X, add = %X",
       gState.isDebugMode, &(gState.isDebugMode),
       gState.aspectRatio, &(gState.aspectRatio),
       gState.canary, &(gState.canary));

canary is being set to 0x12344321

results in:
file1.cpp:

isDebugMode = 1, address = 5BAE20
aspectRatio = 2, address = 5BAE21
canary = 12344321, address = 5BAE25

file2.cpp:

isDebugMode = 1, address = 5BAE20
aspectRatio = 876814592, address = 5BAE24
canary = 12, address = 5BAE28

file1.cpp is correct; file2.cpp isn't. The address for aspectRatio is being bumped by 3. Can anyone tell me what the hell is going on?

Thanks,

earl

PS: struct member alignment is set to 8 bytes in the compilation flags.

-- modified at 20:27 Monday 3rd July, 2006

Re: c++ and external structs

Michael Dunn3-Jul-06 16:59

Michael Dunn

3-Jul-06 16:59

Put a #pragma pack instruction around the struct definition. The compiler option just sets the default packing, some other buggy header may be changing the packing and not resetting it.

--Mike--
Visual C++ MVP Cool | :cool:

LINKS~! Ericahist | PimpFish | CP SearchBar v3.0 | C++ Forum FAQ

VB > soccer

New Dialog in a saved .exe

Reagan Conservative3-Jul-06 7:05

Reagan Conservative

3-Jul-06 7:05

While trying to add a new dialog (for login), after I build the dialog resource and compile the new class, I get errors saying that the IDD_DIALOG1 can't be found, even though it is in the .h file. This is where the error message points back to (the .h file). Anyone know why this is reacting the way it is. This is the first version of Visual C++ 6.0.

Thanks.

John P.

Re: New Dialog in a saved .exe

Zac Howland3-Jul-06 7:10

Zac Howland

3-Jul-06 7:10

Check to make sure that the IDD_DIALOG1 has a unique definition in your resource.h file.

If you decide to become a software engineer, you are signing up to have a 1/2" piece of silicon tell you exactly how stupid you really are for 8 hours a day, 5 days a week

Zac

Re: New Dialog in a saved .exe

Reagan Conservative3-Jul-06 8:20

Reagan Conservative

3-Jul-06 8:20

The IDD_DIALOG1 is unique. Also the ID_EMPID and ID_EMPPIN, for the two text iput boxes also generate errors. This .EXE file was created by a third party and supposedly we can add new items to this workspace/project. Is there any kind of control that the original maker can add in Visual C++ that inhibits or prevents new items from being added?

Thanks for your input.

John P.

Re: New Dialog in a saved .exe

Zac Howland3-Jul-06 8:38

Zac Howland

3-Jul-06 8:38

So, if I understand you correctly, you have the source code for a third party application and are adding a new resource (and corresponding classes) to it?

That being the case, then no, there is nothing they could do to make it so you cannot add a new resource.

What error are you getting exactly?

If you decide to become a software engineer, you are signing up to have a 1/2" piece of silicon tell you exactly how stupid you really are for 8 hours a day, 5 days a week

Zac

Re: New Dialog in a saved .exe

Reagan Conservative3-Jul-06 9:56

Reagan Conservative

3-Jul-06 9:56

For the IDD_DIALOG1, the compiler returns:

error C2065: undeclared identifier

error C2057: expected constant expression

Even though the IDD_DIALOG1 is in the .h file as:

//{{AFX_DATA (CloginDialog)
enum { IDD_DIALOG1 };
CString m_empIDnum;
CString m_empPIN;
//}}AFX_DATA

I also get errors saying that the two CString variables above are "undefined"

This just doesn't make sense since Visual C++ made them part of the code.

Thanks, Zac.

John P.

Re: New Dialog in a saved .exe

Zac Howland3-Jul-06 12:29

Zac Howland

3-Jul-06 12:29

Typically, the ClassWizard will inject the following when creating a new class:

//{{AFX_DATA (CloginDialog)
enum { IDD = IDD_DIALOG1 };
CString m_empIDnum;
CString m_empPIN;
//}}AFX_DATA

Is your class name lowercased like that? Usually you see "CLoginDialog". Chances are it is a typo along those lines somewhere.

If you decide to become a software engineer, you are signing up to have a 1/2" piece of silicon tell you exactly how stupid you really are for 8 hours a day, 5 days a week

Zac

Re: New Dialog in a saved .exe

zeus_master3-Jul-06 15:42

zeus_master

3-Jul-06 15:42

have you add the #include "resource.h" in you application?
in fact, these resource are defined in resource.h.

Re: New Dialog in a saved .exe

Reagan Conservative5-Jul-06 5:40

Reagan Conservative

5-Jul-06 5:40

To all three of you who suggested that I add the resource.h file ---- THANKS.

What can I say but DUH!! Sometimes it's too obvious??

Thanks again!

John P.

Re: New Dialog in a saved .exe

dongqin3-Jul-06 18:41

dongqin

3-Jul-06 18:41

#include "resource.h"

hello

Re: New Dialog in a saved .exe

MANISH RASTOGI3-Jul-06 19:52

MANISH RASTOGI

3-Jul-06 19:52

#include "resource.h" before the class declaration.

MANISH RASTOGI

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