Re: toolchain/53051: __atomic_is_lock_free missing on NetBSD/sparc

[David Young <dyoung%pobox.com@localhost>]

The following reply was made to PR lib/53051; it has been noted by GNATS.

From: David Young <dyoung%pobox.com@localhost>
To: gnats-bugs%NetBSD.org@localhost
Cc: 
Subject: Re: toolchain/53051: __atomic_is_lock_free missing on NetBSD/sparc
Date: Sat, 24 Feb 2018 15:37:03 -0600

 On Sat, Feb 24, 2018 at 08:50:01PM +0000, maya%netbsd.org@localhost wrote:
 > The following reply was made to PR toolchain/53051; it has been noted by GNATS.
 > 
 > From: maya%netbsd.org@localhost
 > To: gnats-bugs%NetBSD.org@localhost
 > Cc: 
 > Subject: Re: toolchain/53051: __atomic_is_lock_free missing on NetBSD/sparc
 > Date: Sat, 24 Feb 2018 20:47:46 +0000
 > 
 >  Never mind, the documentation even says it out loud (thanks for someone
 >  who read it out for me... :-))
 >  
 >       This built-in function returns true if objects of SIZE bytes always
 >       generate lock-free atomic instructions for the target
 >       architecture.  If the built-in function is not known to be
 >       lock-free, a call is made to a runtime routine named
 >       `__atomic_is_lock_free'.
 
 That paragraph may oversimplify things a bit?  What if an object
 is SIZE bytes but not naturally aligned?
 
 Some readers may misunderstand "lock-free" to mean a non-interlocked
 memory access (i.e., without LOCK prefix on x86) such as the
 atomic_*_ni(3) functions provide on NetBSD, when the meaning is more
 like a mutex, unless *I* have misunderstood.
 
 Dave
 
 -- 
 David Young
 dyoung%pobox.com@localhost    Urbana, IL    (217) 721-9981