In article <3b571460$1@post.newsfeeds.com>, "chang"
<chang_shen@progressive.com> wrote:
> If I have a class using STL and in the construction it allocates memory.
> When I
> destory the object, does this memory been freed.
>

No.  That's what the destructor is for.

You must include a destructor to destroy or clean up any resource use
(including memory) made by your classes instance.  This remains true when
contained in an STL container or not.

A destructor can be used to close a file, free memory or any other clean
up action required.  By the way: malloc/free should be dropped in favour
of new/delete in C++.

Regards,
Warwick.

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The following simple program compiles well with Borland 4.5:

#include "map.h"

int main()
{
 map<char, unsigned, less<char> > m;

 return 0;
}

But when compiled with xlC, it yields an error message:

"/local/stl/tree.h", line 56.12: 1540-222: (S)
 "rb_tree<char,pair<const char,unsigned int>,select1st<pair<const char,
 unsigned int>,char>,less<char> >::rb_tree_node" needs a constructor
 because class member "value_field" needs a constructor initializer.
 "tst.C", line 6.9: 1540-207: (I) The previous message applies to the
 definition of template "map<char,unsigned int,less<char> >".
 "/local/stl/defalloc.h", line 74.16: 1540-252: (W) The destructor for
 "pair<const char,unsigned int>" does not exist. The call is ignored.
 "/local/stl/defalloc.h", line 73.13: 1540-207: (I) The previous message
 applies to the definition of template "destroy(pair<const char,unsigned int>*)".

This looks like a bug to me, because "value_field" is "unsigned" here,
and "unsigned" shouldn't need a constructor initializer.

Could anybody comment on this?

Thanks,
 Bernd

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