C++ - struct file_exception {}

[pbartosz]

#include <iostream>

struct exception {};
struct file_exception: public exception {

};

void ex() throw(file_exception) {
throw new file_exception();

}

int main()
{
try {
ex();
}
catch (file_exception) {
std::cout << "catched\n";
}
return 0;

}

I get the message: "terminate called after throwing an instance of
'file_exception*'".
Why can't I catch the file_exception?

 

[Michael Doubez]

#include <iostream>

struct exception {};
struct file_exception: public exception {

};

void ex() throw(file_exception) {
        throw new file_exception();

}

int main()
{
        try {
                ex();
        }
        catch (file_exception) {
                std::cout << "catched\n";
        }
        return 0;

}

I get the message: "terminate called after throwing an instance of
'file_exception*'".
Why can't I catch the file_exception?

Because you are throwing a pointer to a file_exception, try:
throw file_exception();

 

[Ian Collins]

#include<iostream>

struct exception {};
struct file_exception: public exception {

};

You have made just about every mistake there is to make with exceptions!

void ex() throw(file_exception) {
throw new file_exception();

1) Don't use exceptions specifications, they are more trouble than they
are worth. Here you say you will only throw a file_exception, but you
throw a file_exception*.

2) Never throw a pointer to an exception.

}

int main()
{
try {
ex();
}
catch (file_exception) {

Never catch by value, always use a cost reference.

std::cout<< "catched\n";
"caught".

}
return 0;

}

I get the message: "terminate called after throwing an instance of
'file_exception*'".
Why can't I catch the file_exception?

Because you didn't throw what you said you would.

 

[pbartosz]

1) Don't use exceptions specifications, they are more trouble than they

are worth.  Here you say you will only throw a file_exception, but you
throw a file_exception*.

Thanks, I forgot C++ new operator return a pointer, otherwise than
Java new operator.

Never catch by value, always use a cost reference.

Oh, I accidentally changed it while writing post.

Thanks for response.

 

[pbartosz]

1) Don't use exceptions specifications, they are more trouble than they

are worth. Here you say you will only throw a file_exception, but you
throw a file_exception*.

Thanks, I forgot that C++ new operator returns a pointer, otherwise
than
Java new operator.

Never catch by value, always use a cost reference.

Oh, I accidentally changed it before writing post.

Thanks for response.

 

[pbartosz]

1) Don't use exceptions specifications, they are more trouble than they

are worth. Here you say you will only throw a file_exception, but you
throw a file_exception*.

Thanks, I forgot that C++ new operator returns a pointer, otherwise
than Java new operator.

Never catch by value, always use a cost reference.

Oh, I accidentally changed it before writing post.

Thanks for response.

 

[Ian Collins]

Thanks, I forgot that C++ new operator returns a pointer, otherwise
than Java new operator.


Oh, I accidentally changed it before writing post.

Thanks for response.

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