Module Name: src
Committed By: pgoyette
Date: Mon Jul 3 21:16:36 UTC 2017
Modified Files:
src/share/man/man9: condvar.9
Log Message:
Update to include new cv_timedwaitbt() and cv_timedwaitbt_sig().
Also update code example.
OK riastradh@
To generate a diff of this commit:
cvs rdiff -u -r1.14 -r1.15 src/share/man/man9/condvar.9
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/share/man/man9/condvar.9
diff -u src/share/man/man9/condvar.9:1.14 src/share/man/man9/condvar.9:1.15
--- src/share/man/man9/condvar.9:1.14 Thu Dec 2 12:54:13 2010
+++ src/share/man/man9/condvar.9 Mon Jul 3 21:16:36 2017
@@ -1,4 +1,4 @@
-.\" $NetBSD: condvar.9,v 1.14 2010/12/02 12:54:13 wiz Exp $
+.\" $NetBSD: condvar.9,v 1.15 2017/07/03 21:16:36 pgoyette Exp $
.\"
.\" Copyright (c) 2006, 2007, 2008 The NetBSD Foundation, Inc.
.\" All rights reserved.
@@ -27,7 +27,7 @@
.\" ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
.\" POSSIBILITY OF SUCH DAMAGE.
.\"
-.Dd June 4, 2008
+.Dd July 3, 2017
.Dt CONDVAR 9
.Os
.Sh NAME
@@ -39,6 +39,8 @@
.Nm cv_wait_sig ,
.Nm cv_timedwait ,
.Nm cv_timedwait_sig ,
+.Nm cv_timedwaitbt ,
+.Nm cv_timedwaitbt_sig ,
.Nm cv_signal ,
.Nm cv_broadcast ,
.Nm cv_has_waiters
@@ -57,6 +59,12 @@
.Fn cv_timedwait "kcondvar_t *cv" "kmutex_t *mtx" "int ticks"
.Ft int
.Fn cv_timedwait_sig "kcondvar_t *cv" "kmutex_t *mtx" "int ticks"
+.Ft int
+.Fn cv_timedwaitbt "kcondvar_t *cv" "kmutex_t *mtx" "struct bintime *bt" \
+"const struct bintime *epsilon"
+.Ft int
+.Fn cv_timedwaitbt_sig "kcondvar_t *cv" "kmutex_t *mtx" "struct bintime *bt" \
+"const struct bintime *epsilon"
.Ft void
.Fn cv_signal "kcondvar_t *cv"
.Ft void
@@ -192,6 +200,22 @@ As per
but also accepts a timeout value and will return
.Er EWOULDBLOCK
if the timeout expires.
+.It Fn cv_timedwaitbt "cv" "mtx" "bt" "epsilon"
+.It Fn cv_timedwaitbt_sig "cv" "mtx" "bt" "epsilon"
+.Pp
+Similar to
+.Fn cv_timedwait
+and
+.Fn cv_timedwait_sig ,
+however the
+.Fa bintime
+argument is decremented in place with the amount of time actually waited,
+and on return contains the amount of time remaining.
+.Pp
+The
+.Fa epsilon
+argument is currently reserved for future use in choosing between low
+and high-resolution timers.
.It Fn cv_signal "cv"
.Pp
Awaken one LWP (potentially among many) that is waiting on the specified
@@ -240,10 +264,20 @@ Consuming a resource:
mutex_enter(\*[Am]res-\*[Gt]mutex);
/*
- * Wait for the resource to become available.
+ * Wait for the resource to become available. Timeout after
+ * five seconds. If the resource is not available within the
+ * alloted time, return an error.
*/
- while (res-\*[Gt]state == BUSY)
- cv_wait(\*[Am]res-\*[Gt]condvar, \*[Am]res-\*[Gt]mutex);
+ bt.sec = 5;
+ bt.frac = 0;
+ while (res-\*[Gt]state == BUSY \*[Am]\*[Am] (bt.sec || bt.frac))
+ cv_timedwaitbt(\*[Am]res-\*[Gt]condvar, \\
+ \*[Am]res-\*[Gt]mutex, bt, epsilon);
+
+ if (res-\*[Gt]state == BUSY) {
+ mutex_exit(\*[Am]res-\*[Gt]mutex);
+ return ETIMEDOUT;
+ }
/*
* It's now available to us. Take ownership of the
@@ -286,3 +320,9 @@ describes the public interface.
.Sh HISTORY
The CV primitives first appeared in
.Nx 5.0 .
+The
+.Fn cv_timedwaitbt
+and
+.Fn cv_timedwaitbt_sig
+primitives first appeared in
+.Nx 9.0 .
