Am 15.04.2012 16:34, schrieb Blair Zajac:
On 03/08/2012 01:18 PM, stef...@apache.org wrote:
Author: stefan2
Date: Thu Mar 8 21:18:45 2012
New Revision: 1298587
URL: http://svn.apache.org/viewvc?rev=1298587&view=rev
Log:
Define and implement svn_named_atomic__t and associated API.
* subversion/include/private/svn_named_atomic.h
new file, containing the new svn_named_atomic API
* subversion/libsvn_subr/svn_named_atomic.c
new file, implements the new API
* subversion/include/svn_error_codes.h
(SVN_ERR_BAD_ATOMIC): new error code used throughout the new API
* build.conf
(libsvn_subr): add new header to exports
+static apr_int64_t
+synched_add(volatile apr_int64_t *mem, apr_int64_t delta)
+{
+ return *mem += delta;
+}
Is this thread safe? Could the thread after reading *mem be context
switched out, another thread calls synced_add(), then the first thread
does its add and writes the *mem?
No those functions are only thread-safe in
combination with the SYNCHRONIZE macro
(see comment in source code).
-- Stefan^2.
