delete op question. do I need to cast?

[lallous]

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.

 

[JKop]

I wouldn't use "new" here. Use "malloc" and the rest...


-JKop

 

[John Harrison]

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)?

3 is correct.

The struct doesn't have any dtor or ctor() it is just a plain C struct.

That makes no difference as far as correctness goes.

john

 

[Timothy Madden]

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)?

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