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https://issues.apache.org/jira/browse/QPID-2206?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12854309#action_12854309
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Andrew Stitcher commented on QPID-2206:
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I think there are a number of issues with the TSS part of this patch:
1. Using a new pthread_key_create() for each and every TSS variable is a very
bad idea IMO. There is a limit to the number of keys that can be allocated. 128
is a typical value and there is no way to ensure the number of uses in our
code. Of course we also use external libraries which may themselves use an
unknown number of keys. We are also (in the client case) a library in someone
else's executable it would be unfriendly to use large numbers of keys. The
recommended thing to do is to use a single key per program or library.
2. I think putting all the code in a header file is a bad and unnecessary idea.
Particularly there is a non-inline function defined there which would be in the
object files multiple times, and will require the linker to figure out that
it's duplicated.
3. It looks to me that the code has no way to eliminate simultaneous
construction of the same ThreadSpec in multiple threads concurrently, this can
happen if you use a function static __thread which is certainly allowed by the
extension and is a useful thing to do (I'm not sure if our code does this, but
it could).
4. I'm not clear that the equivalent to the construction " __thread int a(456)"
would be dealt with correctly.
5. I think the most viable solution to this problem involves modifying the
qpid::sys::Thread class so that it allocates a single key and then deals with
allocating space in memory refered to by this key when necessary. Unfortunately
I suspect this is considerably more work than this approach, and probably
involves some C++ nasties like in place construction and destruction.
> thread-local storage prevents build on Mac
> ------------------------------------------
>
> Key: QPID-2206
> URL: https://issues.apache.org/jira/browse/QPID-2206
> Project: Qpid
> Issue Type: Bug
> Components: Build Tools
> Affects Versions: 0.5
> Environment: Mac OS X 10.5, Xcode 3.2.1
> Reporter: Aaron Hillegass
> Attachments: qpidc-0.6-no-tss.patch.bz2
>
>
> A lack of thread-local storage prevents a build on the Mac:
> g++ -DHAVE_CONFIG_H -I. -Igen -I./gen -Werror -pedantic -Wall -Wextra
> -Wno-shadow -Wpointer-arith -Wcast-qual -Wcast-align -Wno-long-long
> -Wvolatile-register-var -Winvalid-pch -Wno-system-headers
> -Woverloaded-virtual -g -O2 -MT qpid/sys/posix/AsynchIO.lo -MD -MP -MF
> qpid/sys/posix/.deps/AsynchIO.Tpo -c qpid/sys/posix/AsynchIO.cpp -fno-common
> -DPIC -o qpid/sys/posix/.libs/AsynchIO.o
> qpid/sys/posix/AsynchIO.cpp:61: error: thread-local storage not supported for
> this target
> qpid/sys/posix/AsynchIO.cpp:62: error: thread-local storage not supported for
> this target
> qpid/sys/posix/AsynchIO.cpp:63: error: thread-local storage not supported for
> this target
> qpid/sys/posix/AsynchIO.cpp:64: error: thread-local storage not supported for
> this target
> qpid/sys/posix/AsynchIO.cpp:65: error: thread-local storage not supported for
> this target
> qpid/sys/posix/AsynchIO.cpp:66: error: thread-local storage not supported for
> this target
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