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mdlinux7@yahoo.co.in
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 Posted: Sat Apr 23, 2005 2:19 am Post subject: Throwing destructor and Standard Container |
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Most of the sites have quoted :
Objects with throwing destructors cannot be used in Standard
containers
The following code complies with gcc compiler [3.2.2-5] as i was
expecting the compiler error on the basis of above statement:
#include <iostream>
#include <vector>
using std::vector;
using std::cout;
using std::endl;
class bar
{
public:
bar()
{ cout<<"::Constructor of Bar Called::"<
}
~bar()
{
throw 1;
cout<<"::Destructor Called for Bar class::"<
}
};
typedef vector
main()
{
bar objBar;
barVector bVector;
bVector.push_back(objBar);
}
Could any one guide me that why the above code compiles ?
Regards
Dinesh
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Alf P. Steinbach
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| Posted: Sat Apr 23, 2005 5:16 pm Post subject: Re: Throwing destructor and Standard Container |
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* [email]mdlinux7 (AT) yahoo (DOT) co.in[/email]:
| Quote: | Most of the sites have quoted :
Objects with throwing destructors cannot be used in Standard
containers
The following code complies with gcc compiler [3.2.2-5] as i was
expecting the compiler error on the basis of above statement:
|
Why did you exepect a compiler error for a run-time issue?
| Quote: | #include <iostream
#include
using std::vector;
using std::cout;
using std::endl;
class bar
{
public:
bar()
{ cout<<"::Constructor of Bar Called::"<
}
~bar()
{
throw 1;
cout<<"::Destructor Called for Bar class::"<
}
};
typedef vector
main()
|
'main' must have result type 'int'.
| Quote: | {
bar objBar;
barVector bVector;
bVector.push_back(objBar);
}
Could any one guide me that why the above code compiles ?
|
It shouldn't compile due to missing result type for 'main'; you have a less
than perfect compiler.
--
A: Because it messes up the order in which people normally read text.
Q: Why is it such a bad thing?
A: Top-posting.
Q: What is the most annoying thing on usenet and in e-mail?
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ben
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| Posted: Sun Apr 24, 2005 9:14 am Post subject: Re: Throwing destructor and Standard Container |
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Because the destructor is not DECLARED as one that will throw an exception,
try:
~bar() throw (std::exception);
<mdlinux7 (AT) yahoo (DOT) co.in> wrote
| Quote: | Most of the sites have quoted :
Objects with throwing destructors cannot be used in Standard
containers
The following code complies with gcc compiler [3.2.2-5] as i was
expecting the compiler error on the basis of above statement:
#include <iostream
#include
using std::vector;
using std::cout;
using std::endl;
class bar
{
public:
bar()
{ cout<<"::Constructor of Bar Called::"<
}
~bar()
{
throw 1;
cout<<"::Destructor Called for Bar class::"<
}
};
typedef vector
main()
{
bar objBar;
barVector bVector;
bVector.push_back(objBar);
}
Could any one guide me that why the above code compiles ?
|
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James Kanze
Guest
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| Posted: Sun Apr 24, 2005 8:57 pm Post subject: Re: Throwing destructor and Standard Container |
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[email]mdlinux7 (AT) yahoo (DOT) co.in[/email] wrote:
| Quote: | Most of the sites have quoted :
Objects with throwing destructors cannot be used in Standard
containers
|
Which is correct according to the standard.
| Quote: | The following code complies with gcc compiler [3.2.2-5] as i
was expecting the compiler error on the basis of above
statement:
|
The above statement says that you're not allowed to exit a
destructor via an exception if the object is in a standard
container. It doesn't say that you'll get an error message if
you do. In practice, it's pretty much impossible to know until
runtime anyway.
| Quote: | #include <iostream
#include
using std::vector;
using std::cout;
using std::endl;
class bar
{
public:
bar()
{ cout<<"::Constructor of Bar Called::"<
}
~bar()
{
throw 1;
cout<<"::Destructor Called for Bar class::"<
}
};
typedef vector
main()
{
bar objBar;
barVector bVector;
bVector.push_back(objBar);
}
Could any one guide me that why the above code compiles ?
|
And where would you expect the error? Normally, the
implementation code for the destructor would be in a completely
different module; the compiler cannot see that it throws when it
instantiates the vector, and it cannot see that the object will
be used in a standard container when it compiles the destructor.
--
James Kanze mailto: [email]james.kanze (AT) free (DOT) fr[/email]
Conseils en informatique orientée objet/
Beratung in objektorientierter Datenverarbeitung
9 pl. Pierre Sémard, 78210 St.-Cyr-l'École, France +33 (0)1 30 23 00 34
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Maxim Yegorushkin
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| Posted: Mon Apr 25, 2005 1:19 pm Post subject: Re: Throwing destructor and Standard Container |
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On Sun, 24 Apr 2005 13:14:23 +0400, ben <benhongh (AT) hotmail (DOT) com> wrote:
| Quote: | Because the destructor is not DECLARED as one that will throw an
exception,
try:
~bar() throw (std::exception);
|
It won't not help. The standard does not enforce the rule. Caveat emptor.
--
Maxim Yegorushkin
[ See http://www.gotw.ca/resources/clcm.htm for info about ]
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