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authorTheo de Raadt <deraadt@cvs.openbsd.org>2003-10-04 16:47:18 +0000
committerTheo de Raadt <deraadt@cvs.openbsd.org>2003-10-04 16:47:18 +0000
commit09ba5264ad9970bc5673c1e99472bcb38808508e (patch)
treecb07503383de28a281cd3dc56373e6bc2d32da32
parent8defeb39e797f0002789cfe494a0a335694f41d3 (diff)
clarification of how read works; from d
-rw-r--r--share/man/man4/tb.411
1 files changed, 10 insertions, 1 deletions
diff --git a/share/man/man4/tb.4 b/share/man/man4/tb.4
index 47620422b19..ffb95948d96 100644
--- a/share/man/man4/tb.4
+++ b/share/man/man4/tb.4
@@ -1,4 +1,4 @@
-.\" $OpenBSD: tb.4,v 1.7 2003/07/09 13:26:20 jmc Exp $
+.\" $OpenBSD: tb.4,v 1.8 2003/10/04 16:47:17 deraadt Exp $
.\" $NetBSD: tb.4,v 1.3.6.1 1996/05/31 00:37:45 cgd Exp $
.\"
.\" Copyright (c) 1986, 1991 Regents of the University of California.
@@ -89,6 +89,15 @@ and operating mode by
.Em or Ns -ing
the two values together.
.Pp
+Calling
+.Xr read 2
+on the device always succeeds, returning the last sample,
+although the
+.Xr select 2
+and
+.Xr poll 2
+system calls will correctly report the read state for new samples.
+.Pp
The line discipline supports digitizing devices which are
compatible with Hitachi,
.Tn GTCO ,