Re: C++0x
Erik Wikstr??m ha scritto:
On 2008-05-29 04:27, Mathias Gaunard wrote:
On 28 mai, 00:42, Erik Wikstr??m <Erik-wikst...@telia.com> wrote:
On 2008-05-27 16:33, Mathias Gaunard wrote:
You get the same thing as finally but using an object that takes a
I meant s/but/by/ here, sorry.
Except of course that the function-object does not have access to any
local (or global) variables.
That's called a closure.
All decent lambda expressions DSELs have closure support. And so does
the lambda function C++0x proposal.
I notice that you failed to quote the rest of my post which points out
that you can give the necessary members as arguments to the class'
constructor, but that you will have to write a special class for each
place you want finally. I fail to see how a closure will fix this issue.
// this is all valid C++0x (unless I'm much mistaken ;)
#include <functional>
struct scope_guard
{
std::reference_closure<void()> guard;
scope_guard(const std::reference_closure<void()>& g)
: guard(g)
{}
~scope_guard()
{
guard();
}
};
int f()
{
FILE* f = fopen("file.txt", "r");
scope_guard finally([&](){ fclose(f); }); // lambda expression
// do whatever you want here
} // the destructor of object finally will call fclose(f)
HTH,
Ganesh
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