Submitter:
Submission Date:
Source: Owen Shepherd
Reference Document: N/A
Version:
Date:
Subject: tss_t destruction
unspecified
The standard does not specify if or when destructors for
thread specific data keys (created with
the tss_create function) are
invoked.
This proposal suggests to align the behavior with that
specified by POSIX for pthread_key_t.
This behavior is hoped to both match the intention
of the standard, and be possible to implement on other systems
(it is noted that a pthreads implementation exists for Windows,
for example, while the behavior of POSIX and Windows
thread local storage implementations differ greatly)
After 7.26.5.1p2, add
Returning
from func shall have the same behaviour as
invoking thrd_exit with the returned value
Change 7.26.5.5 parts 2 and 3 from
The
thrd_exit function terminates execution of the
calling thread and sets its result code to
res.
The program shall terminate normally after the last thread has been terminated. The behavior shall be as if the program called the exit function with the status EXIT_SUCCESS at thread termination time.
to
For every thread specific storage
key which was created with a non-NULL destructor and for which
the value is non-NULL, thrd_exit shall set the value
associated with the key to NULL and then invoke the destructor
with its previous value. The order in which destructors are
invoked is unspecified.
If after this process there
remain keys with both non-NULL destructors and values, the
implementation shall repeat this process up
to TSS_DTOR_ITERATIONS times.
If thrd_exit is
not being invoked in the last thread in the process, then the
implementation shall terminate execution of the calling
thread and set its result code to res.
Otherwise, the implementation shall behave as
if exit(EXIT_SUCCESS) was invoked.
(This change provides application writers guarantees about the
identity of the thread executing functions registered
with atexit)
After 7.26.6.1p2, add
The value NULL shall be associated with the newly created key in all existing threads. Upon thread creation, the value associated with all keys shall be initialized to NULL
Note that destructors associated thread specific storage are not invoked at process exit.
To 7.26.6.2p2, append
If tss_delete
is called while another thread is executing destructors, whether
this will affect the number of invocations of the destructor
associated with key on that thread is
unspecified. If the thread from
which tss_delete is invoked is executing
destructors, then no further invocations of the destructor
associated with key will occur on said
thread.
Calling tss_delete will not result in the
invocation of any destructors.
After 7.26.6.4p2, add
This action will not invoke the destructor associated with the key on the value being replaced.