Deleting STL list entry - are all iterators invalidated?

[Boltar]

Hello

I need to iterate through an STL list container and delete certain
entries in it. I realise if use erase() with the iterator it will
invalidate it but what if I store it beforehand? Ie: is the code below
using a 2nd iterator variable always guaranteed to work or could there
be come internal implementation magic going on inside the list that
could prevent it?

for(iter=objlis t.begin();iter != objlist.end();+ +iter)
{
iter2 = iter;
obj = *iter;
obj->run();
if (obj->destroy_me)
{
objlist.erase(i ter);
delete obj;
iter = iter2;
}
}

Thanks for any help.

B2003

[Daniel T.]

In article <11************ **********@l53g 2000cwa.googleg roups.com>,
"Greg" <gr****@pacbell .netwrote:

Daniel T. wrote:

"Boltar" <bo********@yah oo.co.ukwrote:

>
for(iter=objlis t.begin();iter != objlist.end();)
{
iter2 = iter
iter2++;
obj = *iter;
obj->run();
if (obj->destroy_me)
{
objlist.erase(i ter);
delete obj;
iter = iter2;
}
else iter++;
}

Something that should have been a member function of std::list:

template < typeanme T >
void remove_if( std::list<T>& li, Fn fn )
{
typename std::list<T>::i terator it = li.begin();
while ( it != li.end() )
if ( fn( *it ) )
li.erase( it++ );
}

Actually, std::list does have a remove_if() member function.

Well, there you go:

bool should_destroy( MyClass* obj ) {
if ( obj->destroy_me ) {
delete obj;
return true;
}
return false;
}

for_each( objlist.begin() , objlist.end(), mem_fun( &MyClass::ru n ) );
objlist.remove_ if( &should_dest roy );