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u may get some clue from COM(DLL) event. event interface is defined in a share file which is shared by both EXE AND DLL, DLL calls the functions defined by event interface, and exe realizes those functions.
life is like a box of chocolate,you never know what you r going to get.
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hi,
thanks for ur reply..
i want to call a MFC exe from another exe , so that i used shellExecute() to run another exe, at the same time ,i need to pass some parameter values to the another exe, which has to display the values in their corresponding edit box.
for e.g., if i passed "NAME","NUMBER","MARK1"
the another exe display those above information in their edit box.
Try again and again,
At last you will say
I don't know the meaning for impossible.,.
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hi all,
i want to develop one application in VC++.
A win32 dll can make use to call a MFC exe and to pass some argument value to that exe.At last the MFC exe can show the argument values passed by the dll.
A messagebox should be show the argument's value ...
thnaks...
invoke(arguments)
Dll --------> MFC exe ---->MessageBox(arguments..)
Try again and again,
At last you will say
I don't know the meaning for impossible.,.
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Not enough information. The EXE owns the UI thread so unless the DLL starts a worker thread it can't "pass" anything to the EXE. If you just want information "back from" the DLL code then define a structure that the DLL will fill the values of and pass a reference to it into the DLL in a function from the EXE code. When the function returns the structures values are filled in. If this is not your situation then you need to explain it more specifically.
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Hello everyone, could someone help me with this problem
i animate window containing activex flash control, and the window rollouts
but while it's animating it is gray inside, and only when it's fuly visible the activex control appears.
I tryed to catch WM_SIZING but this message won't apear until i try to resize the window by hand.
Anyone knows how to solve that problem, maybe some message that is send by AnimateWindow or any other way.
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Query. Most people from a C background would cast using the x = (type)y; syntax - for example, to convert a long to a short (knowing it won't be truncated of course...):
long aLong = 1234L;
short aShort = (short)aLong;
No problems.
However, I have come across some C++ code that uses the following syntax:
long aLong = 1234L;
short aShort = short(aLong);
Is this alternative syntax C++ only (I assume it is, but a Google seems to come back with conflcting results)? Also, is there any real advantage to either method? Are the various C++ casts (static_cast, dynamic_cast) more useful in casting POD types like this?
I can't believe I haven't come across the x = type(y); syntax before. I asked some other C/C++ old-timers here and they hadn't seen it either. Mad. Always something new to learn!
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Robert Edward Caldecott wrote: I can't believe I haven't come across the x = type(y); syntax before
default constructors...
TOXCCT >>> GEII power
[VisualCalc 3.0 updated ][Flags Beginner's Guide new! ]
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They are syntactically the same. It's much like:
int foo( void )
{
return 12;
}vs.
int foo( void )
{
return (12);
}Some folks use parenthesis with the sizeof operator:
int x = sizeof(obj); while others do not:
int x = sizeof obj;
"Money talks. When my money starts to talk, I get a bill to shut it up." - Frank
"Judge not by the eye but by the heart." - Native American Proverb
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In this case it is the same thing, but in general the syntax you describe is not casting, but initialization.
On the other hand, I like to use C++ casts (static_cast, reinterpret_cast) these days. It is very easy to search for them in the code, unlike the C style casts.
My programming blahblahblah blog. If you ever find anything useful here, please let me know to remove it.
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Nemanja Trifunovic wrote: On the other hand, I like to use C++ casts (static_cast, reinterpret_cast) these days.
Me too, usually - however, when casting POD types like this, is there really any benefit from using static_cast?
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Hmm, for some reason it put my post as a reply to the wrong original post...
DavidCrow wrote: Some folks use parenthesis with the sizeof operator:
int x = sizeof(obj);
while others do not:
int x = sizeof obj;
Actually, sizeof expr does not need parentheses, but sizeof(type) requires them (you can check the C++ grammar). I get a compile error when trying to compile this program:
#include <iostream>
int main()
{
int i = 0;
std::cout << sizeof(i) << '\n';
std::cout << sizeof i << '\n';
std::cout << sizeof(int) << '\n';
std::cout << sizeof int << '\n';
}
--
Marcus Kwok
-- modified at 17:16 Monday 17th July, 2006
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Robert Edward Caldecott wrote: when casting POD types like this, is there really any benefit from using static_cast?
With integral types, and classes/structs without a constructor/destructor, there's no benefit.
"Money talks. When my money starts to talk, I get a bill to shut it up." - Frank
"Judge not by the eye but by the heart." - Native American Proverb
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I stand corrected. I always use parenthesis, regardless of the object, so I've never seen this compiler error. Thanks.
"Money talks. When my money starts to talk, I get a bill to shut it up." - Frank
"Judge not by the eye but by the heart." - Native American Proverb
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Yes there is, visability and clarity.
Steve
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I get the same benefit(s) from C-style casts. It's very clear to me what they are doing. If casting errors are something that a person is prone to making, having the compiler warn of impending danger might be a benefit.
"Money talks. When my money starts to talk, I get a bill to shut it up." - Frank
"Judge not by the eye but by the heart." - Native American Proverb
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C style casts are anything but clear. While C-style casts look simple they are actually very complicated and subtle. In small programs this often goes unnoticed. But as the program gets larger real problems can and do occur. Try this example program. I know it's on the longish side but it's typical of real applications and may suprise you.
The output with the #include is:
Base2
The output without #include is:
Base1
Not many C++ programmers will be able to spot the problem.
--------------------
// Casts.cpp : Defines the entry point for the console application.
//
#include "stdafx.h"
#include <iostream>
#include "Functions.h"
// C-style casts suck. The program will compile with or without the line below using C-style casts.
// With it all is OK, without it the program misbehaves at runtime. If 'static_cast' is used the
// program not compile without the #include and you don't get any nasty suprises.
#include "Classes.h"
int main(int argc, char* argv[])
{
Derived *pDerived = MakeDerived();
DoStuff((Base2*)pDerived);
//DoStuff(static_cast<Base2*>(pDerived));
KillDerived(pDerived);
return 0;
}
\/\/\/\/\/\/
// Classes.h
#ifndef __CLASSES_H__
#define __CLASSES_H__
class Base1
{
public:
Base1();
void Print() const;
private:
const char *m_pName;
};
class Base2
{
public:
Base2();
void Print() const;
private:
const char *m_pName;
};
class Derived : public Base1, public Base2
{
};
#endif // !__CLASSES_H__
\/\/\/\/\/\/
// Functions.h
#ifndef __FUNCTIONS_H__
#define __FUNCTIONS_H__
class Base1;
class Base2;
class Derived;
Derived* MakeDerived();
void KillDerived(Derived *pDerived);
void DoStuff(Base2 *pB2);
#endif // !__FUNCTIONS_H__
\/\/\/\/\/\/
// Implementation.cpp
#include "stdafx.h"
#include "Functions.h"
#include "Classes.h"
#include <iostream>
Base1::Base1()
{
m_pName = "Base1";
}
void Base1::Print() const
{
using namespace std;;
cout << m_pName << endl;
}
Base2::Base2()
{
m_pName = "Base2";
}
void Base2::Print() const
{
using namespace std;;
cout << m_pName << endl;
}
Derived* MakeDerived()
{
return new Derived;
}
void KillDerived(Derived *pDerived)
{
delete pDerived;
}
void DoStuff(Base2 *pB2)
{
pB2->Print();
}
Steve
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in C++ you can (should?) use the static_cast; it takes a little longer to type, but I think it makes casting a lot more clearer.
long aLong = 1234L;
short aShort = static_cast<short>( aLong );
Maximilien Lincourt
Your Head A Splode - Strong Bad
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Maximilien wrote: short aShort = static_cast( aLong );
you meant short aShort = static_cast<short>( aLong ); i believe
TOXCCT >>> GEII power
[VisualCalc 3.0 updated ][Flags Beginner's Guide new! ]
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darn, I forgot the <> get zapped by default.
Maximilien Lincourt
Your Head A Splode - Strong Bad
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Maximilien wrote: I forgot the <> get zapped by default.
The angle brackets are there, just hidden.
"Money talks. When my money starts to talk, I get a bill to shut it up." - Frank
"Judge not by the eye but by the heart." - Native American Proverb
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Robert Edward Caldecott wrote: I can't believe I haven't come across the x = type(y); syntax before. I asked some other C/C++ old-timers here and they hadn't seen it either. Mad. Always something new to learn!
I use it all the time. I use that syntax because it looks like a constructor, rather than a cast. Easier to type than static_cast, and just as easy to search for as static_cast. It's a bit dangerous, as it works like a reinterpret_cast, but hey! I've grown up, and I don't need mommy to hold my hand.  (Lots of drugs are required before I start casting HANDLEs to BYTEs, etc. Since I don't use drugs, I don't worry much about bad casts.  )
--
80 percent entertainment by volume
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Jörgen Sigvardsson wrote: I've grown up, and I don't need mommy to hold my hand. (Lots of drugs are required before I start casting HANDLEs to BYTEs, etc. Since I don't use drugs, I don't worry much about bad casts. )
You may have grown up, but I can almost guarantee that 1) you won't be working at the same place forever 2) some knucklehead will come in and think he can safely cast anything to anything and use your code as an example and 3) you will find out that not using the C++-style casts will create an inconsistent coding style in your developments.
Just an FYI.
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
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Zac Howland wrote: some knucklehead will come in and think he can safely cast anything to anything and use your code as an example
This is the wisest thing I've heard on CP for some time; I agree completely.
Steve
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Stephen Hewitt wrote: This is the wisest thing I've heard on CP for some time; I agree completely.
Thank you. That statement comes from years of watching that exact situation occur time and time again.
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
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Zac Howland wrote: 2) some knucklehead will come in and think he can safely cast anything to anything and use your code as an example
I think casts would be the least of this knuckleheads's troubles if he doesn't understand how casts work in C++. 
Zac Howland wrote: you will find out that not using the C++-style casts will create an inconsistent coding style in your developments.
Yes, and no. If I start mixing the casts, then it'd be inconsistent. I use C++ casts to indicate that something worth paying attention to is happening. For instance - downcasts (static_cast), round-ball-into-square-hole-casts (reinterpret_cast), and dynamic casts (dynamic_cast). In essence, I only to constructor like casts when dealing with integral types. In that code, it's obvious what's going on - no need to pollute the visibility with lots of text.
My 2 cents.
--
As Foretold by NostradamusLast modified: den 17 juli 2006 20:09:40 --
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