diff options
Diffstat (limited to 'nptl/pthread_tryjoin.c')
-rw-r--r-- | nptl/pthread_tryjoin.c | 75 |
1 files changed, 75 insertions, 0 deletions
diff --git a/nptl/pthread_tryjoin.c b/nptl/pthread_tryjoin.c new file mode 100644 index 0000000000..88d2e8bd4e --- /dev/null +++ b/nptl/pthread_tryjoin.c @@ -0,0 +1,75 @@ +/* Copyright (C) 2002 Free Software Foundation, Inc. + This file is part of the GNU C Library. + Contributed by Ulrich Drepper <drepper@redhat.com>, 2002. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, write to the Free + Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA + 02111-1307 USA. */ + +#include <errno.h> +#include <stdlib.h> + +#include "atomic.h" +#include "pthreadP.h" + + +int +pthread_tryjoin_np (threadid, thread_return) + pthread_t threadid; + void **thread_return; +{ + struct pthread *self; + struct pthread *pd = (struct pthread *) threadid; + + /* Make sure the descriptor is valid. */ + if (DEBUGGING_P && __find_in_stack_list (pd) == NULL) + /* Not a valid thread handle. */ + return ESRCH; + + /* Is the thread joinable?. */ + if (IS_DETACHED (pd)) + /* We cannot wait for the thread. */ + return EINVAL; + + self = THREAD_SELF; + if (pd == self || self->joinid == pd) + /* This is a deadlock situation. The threads are waiting for each + other to finish. Note that this is a "may" error. To be 100% + sure we catch this error we would have to lock the data + structures but it is not necessary. In the unlikely case that + two threads are really caught in this situation they will + deadlock. It is the programmer's problem to figure this + out. */ + return EDEADLK; + + /* Return right away if the thread hasn't terminated yet. */ + if (pd->tid != 0) + return EBUSY; + + /* Wait for the thread to finish. If it is already locked something + is wrong. There can only be one waiter. */ + if (atomic_compare_and_exchange_acq (&pd->joinid, self, NULL) != 0) + /* There is already somebody waiting for the thread. */ + return EINVAL; + + /* Store the return value if the caller is interested. */ + if (thread_return != NULL) + *thread_return = pd->result; + + + /* Free the TCB. */ + __free_tcb (pd); + + return 0; +} |