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lallous
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 Posted: Mon Sep 27, 2004 9:32 am Post subject: delete op question. do I need to cast? |
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Hello
Consider this:
// allocate a buffer, and cast to MYSTRUCT
MYSTRUCT *p = (MYSTRUCT *) new char[sizeof(MYSTRUCT) + 100];
// free the buffer
// 1. can I free directly as:
delete [] p;
// 2. or as:
delete p;
// 3. or better, to cast to char* and delete, as:
delete [] (char *)p;
Which is correct (if any)?
The struct doesn't have any dtor or ctor() it is just a plain C struct.
--
Elias
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JKop
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| Posted: Mon Sep 27, 2004 10:01 am Post subject: Re: delete op question. do I need to cast? |
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I wouldn't use "new" here. Use "malloc" and the rest...
-JKop
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John Harrison
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| Posted: Mon Sep 27, 2004 10:01 am Post subject: Re: delete op question. do I need to cast? |
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"lallous" <lallous (AT) lgwm (DOT) org> wrote
| Quote: | Hello
Consider this:
// allocate a buffer, and cast to MYSTRUCT
MYSTRUCT *p = (MYSTRUCT *) new char[sizeof(MYSTRUCT) + 100];
// free the buffer
// 1. can I free directly as:
delete [] p;
// 2. or as:
delete p;
// 3. or better, to cast to char* and delete, as:
delete [] (char *)p;
Which is correct (if any)?
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3 is correct.
| Quote: | The struct doesn't have any dtor or ctor() it is just a plain C struct.
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That makes no difference as far as correctness goes.
john
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Timothy Madden
Guest
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| Posted: Mon Sep 27, 2004 10:04 am Post subject: Re: delete op question. do I need to cast? |
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"lallous" <lallous (AT) lgwm (DOT) org> wrote
| Quote: | Hello
Consider this:
// allocate a buffer, and cast to MYSTRUCT
MYSTRUCT *p = (MYSTRUCT *) new char[sizeof(MYSTRUCT) + 100];
// free the buffer
// 1. can I free directly as:
delete [] p;
// 2. or as:
delete p;
// 3. or better, to cast to char* and delete, as:
delete [] (char *)p;
Which is correct (if any)?
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Of course
delete [] (char *)p;
is correct.
Use typecasts only when necessary. They bypass the type-checking rules of
the language.
Also if you have some dlls take care to delete from the same module where
you allocated the data with new.
Timothy Madden
Romania
-----------------------------------------------
And I don't wanna miss a thing
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