[libstdc++] remove __compare_and_swap

Nathan Myers ncm@nospam.cantrip.org
Fri Oct 5 12:19:00 GMT 2001


On Fri, Oct 05, 2001 at 02:45:08PM -0400, Phil Edwards wrote:
> 
> A couple weeks ago I proposed removing __compare_and_swap, an unused 
> function from the CPU configuration headers that seems to confuse port
> maintainers:
> 
>     http://gcc.gnu.org/ml/libstdc++/2001-09/msg00069.html

I apologize for not responding to the previous message.

Compare-and-swap is an essential primitive to maintain linked data 
structures thread-safely without using an enormously more expensive,
unportable, and otherwise problematical mutex.

We don't have much in the library yet for support of multithreaded
programs, but eliminating primitives that such support would need 
seems like the wrong direction to go.

Nathan Myers
ncm at cantrip dot org



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