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authorNeil Jerram <neil@ossau.uklinux.net>2008-03-08 16:22:40 +0000
committerNeil Jerram <neil@ossau.uklinux.net>2008-03-08 16:22:40 +0000
commit6180e336b297560db1ca2e121ffbb34379455fe4 (patch)
treeef2273597084ad19c7589da7c7bc900bd73358dd /doc/ref/api-scheduling.texi
parent61b6542aa618902422c8707793ff57f947631a65 (diff)
downloadguile-6180e336b297560db1ca2e121ffbb34379455fe4.tar.gz
Core enhancements, by Julian Graham, to Guile's thread, mutex and
condvar primitives, in preparation for SRFI-18 support.
Diffstat (limited to 'doc/ref/api-scheduling.texi')
-rw-r--r--doc/ref/api-scheduling.texi87
1 files changed, 77 insertions, 10 deletions
diff --git a/doc/ref/api-scheduling.texi b/doc/ref/api-scheduling.texi
index 56fa20228..7f405064d 100644
--- a/doc/ref/api-scheduling.texi
+++ b/doc/ref/api-scheduling.texi
@@ -267,12 +267,24 @@ Once @var{body} or @var{handler} returns, the return value is made the
@emph{exit value} of the thread and the thread is terminated.
@end deftypefn
+@deffn {Scheme Procedure} thread? obj
+@deffnx {C Function} scm_thread_p (obj)
+Return @code{#t} iff @var{obj} is a thread; otherwise, return
+@code{#f}.
+@end deffn
+
@c begin (texi-doc-string "guile" "join-thread")
-@deffn {Scheme Procedure} join-thread thread
+@deffn {Scheme Procedure} join-thread thread [timeout [timeoutval]]
@deffnx {C Function} scm_join_thread (thread)
+@deffnx {C Function} scm_join_thread_timed (thread, timeout, timeoutval)
Wait for @var{thread} to terminate and return its exit value. Threads
that have not been created with @code{call-with-new-thread} or
-@code{scm_spawn_thread} have an exit value of @code{#f}.
+@code{scm_spawn_thread} have an exit value of @code{#f}. When
+@var{timeout} is given, it specifies a point in time where the waiting
+should be aborted. It can be either an integer as returned by
+@code{current-time} or a pair as returned by @code{gettimeofday}.
+When the waiting is aborted, @var{timeoutval} is returned (if it is
+specified; @code{#f} is returned otherwise).
@end deffn
@deffn {Scheme Procedure} thread-exited? thread
@@ -363,21 +375,51 @@ Acquiring requisite mutexes in a fixed order (like always A before B)
in all threads is one way to avoid such problems.
@sp 1
-@deffn {Scheme Procedure} make-mutex
+@deffn {Scheme Procedure} make-mutex . flags
@deffnx {C Function} scm_make_mutex ()
-Return a new standard mutex. It is initially unlocked.
+@deffnx {C Function} scm_make_mutex_with_flags (SCM flag)
+Return a new mutex. It is initially unlocked. If @var{flags} is
+specified, it must be a list of symbols specifying configuration flags
+for the newly-created mutex. The supported flags are:
+@table @code
+@item unchecked-unlock
+Unless this flag is present, a call to `unlock-mutex' on the returned
+mutex when it is already unlocked will cause an error to be signalled.
+
+@item allow-external-unlock
+Allow the returned mutex to be unlocked by the calling thread even if
+it was originally locked by a different thread.
+
+@item recursive
+The returned mutex will be recursive.
+
+@end table
+@end deffn
+
+@deffn {Scheme Procedure} mutex? obj
+@deffnx {C Function} scm_mutex_p (obj)
+Return @code{#t} iff @var{obj} is a mutex; otherwise, return
+@code{#f}.
@end deffn
@deffn {Scheme Procedure} make-recursive-mutex
@deffnx {C Function} scm_make_recursive_mutex ()
-Create a new recursive mutex. It is initialloy unlocked.
+Create a new recursive mutex. It is initially unlocked. Calling this
+function is equivalent to calling `make-mutex' and specifying the
+@code{recursive} flag.
@end deffn
-@deffn {Scheme Procedure} lock-mutex mutex
+@deffn {Scheme Procedure} lock-mutex mutex [timeout]
@deffnx {C Function} scm_lock_mutex (mutex)
+@deffnx {C Function} scm_lock_mutex_timed (mutex, timeout)
Lock @var{mutex}. If the mutex is already locked by another thread
then block and return only when @var{mutex} has been acquired.
+When @var{timeout} is given, it specifies a point in time where the
+waiting should be aborted. It can be either an integer as returned
+by @code{current-time} or a pair as returned by @code{gettimeofday}.
+When the waiting is aborted, @code{#f} is returned.
+
For standard mutexes (@code{make-mutex}), and error is signalled if
the thread has itself already locked @var{mutex}.
@@ -386,6 +428,10 @@ itself already locked @var{mutex}, then a further @code{lock-mutex}
call increments the lock count. An additional @code{unlock-mutex}
will be required to finally release.
+If @var{mutex} was locked by a thread that exited before unlocking it,
+the next attempt to lock @var{mutex} will succeed, but
+@code{abandoned-mutex-error} will be signalled.
+
When a system async (@pxref{System asyncs}) is activated for a thread
blocked in @code{lock-mutex}, the wait is interrupted and the async is
executed. When the async returns, the wait resumes.
@@ -395,7 +441,7 @@ executed. When the async returns, the wait resumes.
Arrange for @var{mutex} to be locked whenever the current dynwind
context is entered and to be unlocked when it is exited.
@end deftypefn
-
+
@deffn {Scheme Procedure} try-mutex mx
@deffnx {C Function} scm_try_mutex (mx)
Try to lock @var{mutex} as per @code{lock-mutex}. If @var{mutex} can
@@ -404,10 +450,25 @@ If @var{mutex} is locked by some other thread then nothing is done and
the return is @code{#f}.
@end deffn
-@deffn {Scheme Procedure} unlock-mutex mutex
+@deffn {Scheme Procedure} unlock-mutex mutex [condvar [timeout]]
@deffnx {C Function} scm_unlock_mutex (mutex)
-Unlock @var{mutex}. An error is signalled if @var{mutex} is not
-locked by the calling thread.
+@deffnx {C Function} scm_unlock_mutex_timed (mutex, condvar, timeout)
+Unlock @var{mutex}. An error is signalled if @var{mutex} is not locked
+and was not created with the @code{unchecked-unlock} flag set, or if
+@var{mutex} is locked by a thread other than the calling thread and was
+not created with the @code{allow-external-unlock} flag set.
+
+If @var{condvar} is given, it specifies a condition variable upon
+which the calling thread will wait to be signalled before returning.
+(This behavior is very similar to that of
+@code{wait-condition-variable}, except that the mutex is left in an
+unlocked state when the function returns.)
+
+When @var{timeout} is also given, it specifies a point in time where
+the waiting should be aborted. It can be either an integer as
+returned by @code{current-time} or a pair as returned by
+@code{gettimeofday}. When the waiting is aborted, @code{#f} is
+returned. Otherwise the function returns @code{#t}.
@end deffn
@deffn {Scheme Procedure} make-condition-variable
@@ -415,6 +476,12 @@ locked by the calling thread.
Return a new condition variable.
@end deffn
+@deffn {Scheme Procedure} condition-variable? obj
+@deffnx {C Function} scm_condition_variable_p (obj)
+Return @code{#t} iff @var{obj} is a condition variable; otherwise,
+return @code{#f}.
+@end deffn
+
@deffn {Scheme Procedure} wait-condition-variable condvar mutex [time]
@deffnx {C Function} scm_wait_condition_variable (condvar, mutex, time)
Wait until @var{condvar} has been signalled. While waiting,