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Hey, i just wanted to ask if theres a way i can read the data of a file so i can paste it to another file?
Like i read the data of cmd.exe and paste it to whatever.exe?
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Please be clear what you are asking.
ALLERSLIT wrote: i can read the data of a file so i can paste it to another file?
cmd.exe is not a file to be read from, it's an executable.
I know the language. I've read a book. - _Madmatt
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Executables are files though
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and an ice cube is water. What's your point?
I know the language. I've read a book. - _Madmatt
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That it's fine to read from cmd.exe, it's just unusual
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I believe we are going to need more details about what you want to do...till now it sounds like you either want to read file data to the clipboard to paste it somewhere OR you need a filecopy method (like copy in a dos prompt).
> The problem with computers is that they do what you tell them to do and not what you want them to do. <
> "It doesn't work, fix it" does not qualify as a bug report. <
> Amazing what new features none of the programmers working on the project ever heard of you can learn about when reading what the marketing guys wrote about it. <
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I want to create a program out of a program.
We all have a cmd.exe in our windows folder, how would i be able to create the cmd.exe out of my own program?
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What would your program do?
> The problem with computers is that they do what you tell them to do and not what you want them to do. <
> "It doesn't work, fix it" does not qualify as a bug report. <
> Amazing what new features none of the programmers working on the project ever heard of you can learn about when reading what the marketing guys wrote about it. <
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Are you asking how to find executable code inside a program and copy it to another file, in order to run it?
If so, you have to learn the structure of the program.
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ALLERSLIT wrote: Hey, i just wanted to ask if theres a way i can read the data of a file so i can paste it to another file?
Like i read the data of cmd.exe and paste it to whatever.exe?
back in the 1990's, all programs started at the same offset. This made chaining programs easy. In fact a tool called LzExe[^] would compress an executable code, replace the loader function, and chain to the offset starting block.
Now it is a little more difficult. Without knowing your intentions, few people here are likely to give you a step-by-step walk-through. The process is similar, but you will have to read the EXE header and still replace it, that much remains the same, chaining to the code is a little more difficult, but not impossible, but the act of which will cause any security product on the machine such as anti-virus software to halt your action.
If your intent is only to insert program code into a process there are other safer ways to do this without modifying an executable. Dlls offer the safest disk method of injecting code into programs. There are also active methods of inserting code into running processes.
So.... as others have asked, what exactly are you trying to do? modify an executable inserting your own code? for what reason? what are you trying to accomplish?
_________________________
John Andrew Holmes "It is well to remember that the entire universe, with one trifling exception, is composed of others."
Shhhhh.... I am not really here. I am a figment of your imagination.... I am still in my cave so this must be an illusion....
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You already asked this question (although in a slightly different way) here[^]. Reading the contents of an executable file and writing it somewhere else is the same as reading and writing any file; files are composed of bytes and bytes are bytes are bytes. In either case your objective is not clear, try rewording your question to clarify what problem you are actually trying to solve.
It's time for a new signature.
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Why array starts with zero?
Best wishes
Nikesh
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Because it's natural.
-- the C developer
...Or [^].
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
This is going on my arrogant assumptions. You may have a superb reason why I'm completely wrong.
-- Iain Clarke
[My articles]
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Because 0 is the starting number
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(probably not the best technical explanation, but...)
because the first element is at a zero "offset" from the start of the array.
Watched code never compiles.
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Maximilien wrote: probably not the best technical explanation
But may well be the clearest 
It's time for a new signature.
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Watched code never compiles.
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it makes switching between (pointer + offset) and pointer[offset] simple.
if arrays started with 1, pointer[1] would be the same as pointer + 0, and C programs would be full of off-by-one errors as programmers forgot to account for the difference when switching between array notation and pointer + offset notation.
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Can anyone point me to any open source application using exception handling? I have never used EH myself nor ever felt the need to use it. Just wondering what and when is the right use for it?
I want to see how other ppl use exception handling in their code and how does it make their program robust?
one good thing about EH is to quickly exit from deeply nested hierarchy. but how do experts use it?
How often do you use EH in your code?
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For questions like this it's always worth checking Google and/or CodeProject articles[^].
It's time for a new signature.
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One example is the standard library itself:
A stream ask a buffer to read.
If the buffer cannot complain, throws a runtime error that the stream catches, and set its own badbit, so that further reading are discarded in advance.
Believable or not, every software using C++ streams uses exception handling, at least just because of that.
----
Going more personal, wherever you're implementing something at low level that may -in certain RARE condition or in certain WRONG USAGE- not behave correctly, you can throw an exception.
The idea is to manage all those "rare events" not in the "return chain", but at "some point enough hight", typically not necessarily to have a plai n recover, but attempt a clean exit, at least at a level that allows a clean restart.
This works great especially when tighted to technics like RAII, and self-cleaning objects.
2 bugs found.
> recompile ...
65534 bugs found.
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Sorry, most of the open source code I use comes from the Linux community and they're not great fans of C++. As a few guidelines:
You generally don't handle exceptions that often. Usually an exception means that something has gone horribly wrong and it's game over folks, let's just clean up and hope a restart gives a better result.
So generally you'd use an exception handler around main() for a console application and that's about it:
int main()
try
{
}
catch( std::exception &e )
{
std::cout << "Something went wrong: " << e.what() << std::endl;
}
catch( ... )
{
std::cout << "Something went wrong, no idea what!" << std::endl;
}
If you're writing a shared library or DLL with a C interface you'll want to catch exceptions before exiting a cdecl function. C (and other programming languages) don't know about C++ exceptions so it's a bit rude to through one at them.
The same goes for callbacks which go through any third party libraries (e.g. windows procedures in Windows). They may or may not have the same exception strategy and may not be able to handle them.
Cheers,
Ash
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I tend to use assert a lot to check on things as its one way to keep code from crapping out.
http://www.contract-developer.tk
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If you mean C style assert then I'd have to disagree with you and say it's just about useless, except for one edge case. The reason being is that C style assert is meant to be turned off when you build your final code, which can change your program's observable behaviour and I don't want the safety checks I think are important pulled out when I need them - i.e. when my code meets a user!
The edge case is using C style assert to as your tool to do Test Driven Development in a tools challenged environment. Having something that does a boolean test and informs the user if it's false is the minimum you need to do TDD and C style assert fits the bit adequately.
If you mean "assert" as in the general concept of checking preconditions, postconditions and class invariants then you've bought into Design By Contract and haven't got a lot of choice. In that case though you use assertions to generate an exception if the pre/postcondition is not true or the invariant is broken. I don't tend to use DBC that formally (it's a pain in the arse with C++ as the conditions end up embedded in every method and you have to manually check invariance) but the concepts are good. I've found that having a good set of unit tests from TDD is a good way of checking post conditions for example.
Cheers,
Ash
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In general I don't approve of this use of catch (...). As with any rule of thumb there are exceptions but here's my policy on catch (...):
In general you should only catch what you expect could be thrown because catching an unknown exception could result in continued execution when the application is in an inconsistent state. Since catch (...) catches everything it should be avoid. One notable exception is the pattern shown below:
try
{
}
catch (...)
{
throw;
}
Also note that by not using catch (...) or using it only when re-throwing means that the call stack to the unexpected exception is available in the crash dump. Another pitfall is centred around the /EH[^] switch, or older MS compilers, but I won't go into that now.
Steve
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