[LLVMdev] Using C++'11 language features in LLVM itself

greened at obbligato.org greened at obbligato.org
Tue Jan 8 20:44:14 PST 2013

Karen Shaeffer <shaeffer at neuralscape.com> writes:

> I am also aware of the way too common problem of folks stuck in a time
> warp, because they have dependencies on old libraries that they cannot
> upgrade. IMO, a development effort should not slow the pace of feature
> adoption to support folks who have not planned for future upgrades in
> an intelligent manner. Rather than make everyone pay the price for
> such groups, there ought to be a way for them to use an older release
> of llvm until they figure out how to upgrade.

That's pretty harsh.  Vendors depend on other vendors.  If suppliers
don't offer a later version, then either the primary vendor has to
implement a workaround or the primary vendor has to hold back.  That's
an important decision that comes up A LOT and the answer is different
for every situation.

People generally aren't stupid.  They're doing what makes the most sense
for them in their particular situation.

I am of course speaking in generalities, not specifically to C++
libraries and compilers.

> I recommend targeting 4.7.2 or later, because all new C++ code on
> linux is surely going down that path. You can inconvenience the
> laggards, or you can turn away the folks leading the way with new
> implementations. But you can't satisfy both.

4.7 doesn't actually have that many new language features than 4.6.  I
don't know about the std library, that may be quite different.

I don't see a compelling reason to go to 4.7 quite yet.  It might make
more sense to go with 4.6 now and see how the 4.8 C++11 implementation
looks when it arrives.


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