Neal H. Walfield neal@walfield.org
Mon Jan 21 23:27:00 GMT 2008

At Mon, 21 Jan 2008 12:12:23 -0500,
Jeff Johnston wrote:
> The code that uses HAVE_DD_LOCK in libc/posix was taken from an existing 
> code base (IIRC FreeBSD).
> The code in libc/posix is offered optionally to platforms.  The dir 
> family routines code there can be ignored if the platform already 
> supplies these functions (via the flag HAVE_OPENDIR).  If not 
> short-circuited via HAVE_OPENDIR, a port must implement sys/dirent.h or 
> else the code will not build to begin with as you are probably already 
> well-aware.  A platform can also build these and also override them in 
> either the libc/machine/xxx or libc/sys/xxxx directories.
> So, if you choose to build the functions in libc/posix for your platform 
> and you do not short-circuit them with HAVE_OPENDIR and do not override 
> them yourself in your libc/sys directory and you support 
> multi-threading, then you had either better implement the dd_lock field 
> and set HAVE_DD_LOCK or else document that those functions are not 
> thread-safe.

Does that mean you agree that !__SINGLE_THREAD__ implies HAVE_DD_LOCK?
(A simple fix would be s/HAVE_DD_LOCK/!__SINGLE_THREAD__/g.)


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