> On Feb 27, 2018, at 1:05 PM, Sophia Poirier [dfx] > <[email protected]> wrote: > > What would memcpy even be locking to protect/serialize? The caller provides > all of the data used in the function. So if the data needs serialization > with other threads, that is the caller's responsibility.
made no sense to me.. but I’m just being paranoid. Looking at the source does put it to rest — thanks for the link. -m > > By the way, any libc and libc++ library functions have open source > implementations for most compilers. Here you can confirm memcpy lack of > locking on Apple platforms: > > https://opensource.apple.com/source/xnu/xnu-2050.18.24/libsyscall/wrappers/memcpy.c > > <https://opensource.apple.com/source/xnu/xnu-2050.18.24/libsyscall/wrappers/memcpy.c> > > - Sophia > > >> On Feb 27, 2018, at 12:00 PM, Matt Ingalls wrote: >> >> OK thanks >> >>> I would be very surprised if memcpy() were on a list of functions that lock. >> >> Yeah me too, but I wanted to be absolutely sure. >> Even googling “memcpy thread safe” came up with a(n unverified) comment that >> it IS on Solaris, which probably means it takes a mutex, right? >> >> Perhaps my question here really should have been: “where can I find a list >> of common functions that never lock?” :) >> >> >>> dispatch_async() is completely different from vDSP. >> >> Well I said that to say if dispatch_async isn’t lock-free, then that means >> GCD isn't entirely either. >> And the (typically vague) apple documentation says "many vecLib routines >> used multiple POSIX threads...In OS X v10.7, these routines use Grand >> Central Dispatch” >> And since vDSP is part of vecLib…what else can I conclude? >> >> -m > _______________________________________________ > Do not post admin requests to the list. They will be ignored. > Coreaudio-api mailing list ([email protected]) > Help/Unsubscribe/Update your Subscription: > https://lists.apple.com/mailman/options/coreaudio-api/matt%408dio.com > > This email sent to [email protected]
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