OSDev.org

earlz wrote: [rant]
Trying to follow strict C++ orthodoxy is just insane. For instance, what about command line arguments? like

Code: Select all

MyFileClass myfile;

int main(argc,argv){
myfile.load(argv[1]);
}

That according to some people would be bad C++ coding. Because myfile can be accessed before it is constructed.

#include <iostream>
using namespace std;

class MyTestClass {
public:
	MyTestClass();
	~MyTestClass();
	
	void TestFunction();
};

MyTestClass::MyTestClass() {
	cout << "MyTestClass constructor called" << endl;
}

MyTestClass::~MyTestClass() {
	cout << "MyTestClass destructor called" << endl;
}

void MyTestClass::TestFunction() {
	cout << "!! Test Function !!" << endl;
}

MyTestClass testClass;

int main(int argc, char *argv[]) {
	cout << "main() has started..." << endl;
	testClass.TestFunction();
	cout << "main() is finished!" << endl;
	return 0;
}

MyTestClass constructor called
main() has started...
!! Test Function !!
main() is finished!
MyTestClass destructor called

berkus wrote:

quok wrote:I personally don't think unit tests are a useful form of testing, especially for OS development where the modules are so dependent. Getting a unit test set up with a simulated environment is a lot of effort and, again, you have to test the correctness of your simulation. Does that call for a unit test too?

Testing some core classes like containers, string, etc, which are quite easy to test with a simple set of input data but ensures correct operation of other classes that build on these basic structures is quite a good move. And it actually saves you quite a bit of time and nerve when you know that it's not your linked list implementation that is suddenly incorrect, it is something else.

bewing wrote:I am an inventor, not an engineer. I scoff at engineers.

bewing wrote:If you always follow the standards, you will never ever discover a significantly better way of doing anything.

bewing wrote:The reason the shortcuts exist in the first place is that programmers who are willing to experiment a little have found those shortcuts to be a significant improvement to the code, in some way.

bewing wrote:Religiously avoiding them is pedantic and shortsighted.

bewing wrote:

Solar wrote: In a programming language, there are only two ways to do anything: The correct one, and all the others.

No, there are a million ways of doing everything. 99.9% of it comes under the header of "individual taste". What some committee considers "wrong" is just a matter of the personal tastes of a majority of the people who happened to muscle their way onto the committee. To follow blindly is to be a sheep.

bewing wrote:

And because they were good, they were accepted into the standard (like // was).

Until enough programmers break the rules, no change ever gets added to the standard. You argument is circular, and therefore irrational.

bewing wrote:What some committee considers "wrong" is just a matter of the personal tastes of a majority of the people who happened to muscle their way onto the committee.

To follow blindly is to be a sheep.

Strictly follow K&R standards if you want to write REAL C.

Until enough programmers break the rules, no change ever gets added to the standard. You argument is circular, and therefore irrational.

Colonel Kernel wrote: As for my kernel, I have no problems using gcc-specific features. I have no plans to port it to a different compiler... I will probably re-write it in another language first.

ucosty wrote:

earlz wrote: [rant]
Trying to follow strict C++ orthodoxy is just insane. For instance, what about command line arguments? like

Code: Select all

MyFileClass myfile;

int main(argc,argv){
myfile.load(argv[1]);
}

That according to some people would be bad C++ coding. Because myfile can be accessed before it is constructed.

Not true at all. Global objects, like myfile in your example, have their constructors run before main() is run.

http://www.yancy.org/research/library_m ... node4.html

Code: Select all

#include <iostream>
using namespace std;

class MyTestClass {
public:
	MyTestClass();
	~MyTestClass();
	
	void TestFunction();
};

MyTestClass::MyTestClass() {
	cout << "MyTestClass constructor called" << endl;
}

MyTestClass::~MyTestClass() {
	cout << "MyTestClass destructor called" << endl;
}

void MyTestClass::TestFunction() {
	cout << "!! Test Function !!" << endl;
}

MyTestClass testClass;

int main(int argc, char *argv[]) {
	cout << "main() has started..." << endl;
	testClass.TestFunction();
	cout << "main() is finished!" << endl;
	return 0;
}

The example above produces the following output

Code: Select all

MyTestClass constructor called
main() has started...
!! Test Function !!
main() is finished!
MyTestClass destructor called

This clearly shows the constructor running before main() is called.

Solar wrote: And one of his favourite pranks is to challenge a C++ coder to write a fully standard-compliant "Hello World". 90% (!!!) of the people fail that little test, because they are too lazy to ever have learned the language correctly. I came close, I made only one mistake instead of the usual 2-3...

earlz wrote:now pass a command line argument from main() into a global constructor.

Hmmmm, how on earth do you expect that this will be possible? Global constructors execute before main(). Isn't this argument a bit silly since you complained about being able to access a object before it is constructed?

earlz wrote:

Hmmmm, how on earth do you expect that this will be possible? Global constructors execute before main(). Isn't this argument a bit silly since you complained about being able to access a object before it is constructed?

Assuming the programmer knows what he is doing... It should be possible to construct an object before accessing it... like.. I always though references should have been able to be used at the global scope.. A ordered construction at runtime...

clange wrote:

Solar wrote: And one of his favourite pranks is to challenge a C++ coder to write a fully standard-compliant "Hello World". 90% (!!!) of the people fail that little test, because they are too lazy to ever have learned the language correctly. I came close, I made only one mistake instead of the usual 2-3...

Could you please share the correct solution.

#include <iostream>
#include <ostream>

int main()
{
    std::cout << "Hello World" << std::endl;
    return 0;
}

The most common mistake is omitting the <ostream> include

Combuster wrote:And I'd have used "using namespace std;" but I guess that's more a taste thing...