Re: fwd declaring STL containers
Mark P wrote:
LR wrote:
[..]
Now I'm curious. How does this simplify client syntax?
Compare the following two declarations:
std::map<Key, Ty, std::less<Key>,
myAlloc<std::pair<const Key,Ty> > > myMap;
my_map<Key,Ty>::Type myMap;
The issue is that the allocator parameter is the last among all
parameters so to override the default it's necessary to specify all
parameters. Compound this with the particularly unwieldy value_type
of the map, and it gets pretty ugly.
Yes, when you want to supply some kind of pre-defined umpteenth template
argument, then a typedef is an easy way out. But how often do you have
to do that, really? I guess that along with a custom allocator you could
define your own typedefs for using the same allocator with the standard
containers... But that would be also hiding the fact that a custom
allocator is used... I just prefer everything explicit.
V
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