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963. Various threading bugs #13

Section: 32.4.3.6 [thread.thread.member] Status: C++11 Submitter: Pete Becker Opened: 2009-01-07 Last modified: 2016-01-28

Priority: Not Prioritized

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Discussion:

32.4.3.6 [thread.thread.member]: thread::detach is required to throw an exception if the thread is "not a detachable thread". "Detachable" is never defined.

[ Howard adds: ]

Due to a mistake on my part, 3 proposed resolutions appeared at approximately the same time. They are all three noted below in the discussion.

[ Summit, proposed resolution: ]

In 32.4.3.6 [thread.thread.member] change: 

void detach();

...

-14- Error conditions:

  • no_such_process -- if the thread is not a valid thread.
  • invalid_argument -- if the thread is not a detachable joinable thread.

[ Post Summit, Jonathan Wakely adds: ]

A thread is detachable if it is joinable. As we've defined joinable, we can just use that.

This corresponds to the pthreads specification, where pthread_detach fails if the thread is not joinable:

EINVAL: The implementation has detected that the value specified by thread does not refer to a joinable thread.

Jonathan recommends this proposed wording:

In 32.4.3.6 [thread.thread.member] change: 

void detach();

...

-14- Error conditions:

  • ...
  • invalid_argument -- not a detachable joinable thread.

[ Post Summit, Anthony Williams adds: ]

This is covered by the precondition that joinable() be true.

Anthony recommends this proposed wording:

In 32.4.3.6 [thread.thread.member] change: 

void detach();

...

-14- Error conditions:

  • ...
  • invalid_argument -- not a detachable thread.

[ 2009-10 Santa Cruz: ]

Mark as Ready with proposed resolution from Summit.

Proposed resolution:

In 32.4.3.6 [thread.thread.member] change: 

void detach();

...

-14- Error conditions: