Improvements to markup.

share/man/man2/ucontext.2

@@ -1,4 +1,4 @@
-.\"	$NetBSD: ucontext.2,v 1.3 2008/04/30 13:10:53 martin Exp $
+.\"	$NetBSD: ucontext.2,v 1.4 2010/04/28 13:23:02 jruoho Exp $
 .\"
 .\" Copyright (c) 2001 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 13, 2001
+.Dd April 28, 2010
 .Dt UCONTEXT 2
 .Os
 .Sh NAME
@@ -36,17 +36,21 @@
 .Sh SYNOPSIS
 .In ucontext.h
 .Sh DESCRIPTION
-.Nm ucontext_t
+The
+.Vt ucontext_t
 is a structure type which is used to describe the context of a
 thread of control within the execution of a process.
+A thread's context includes its stack, saved registers, and list of
+blocked signals.
 .Pp
-.Nm ucontext_t
-includes the following members:
+The
+.Vt ucontext_t
+structure includes the following members:
 .Bd -literal -offset indent
-ucontext_t *  uc_link
-sigset_t      uc_sigmask
-stack_t       uc_stack
-mcontext_t    uc_mcontext
+ucontext_t *uc_link
+sigset_t    uc_sigmask
+stack_t     uc_stack
+mcontext_t  uc_mcontext
 .Ed
 .Pp
 The
@@ -57,7 +61,9 @@ specified when modifying a context using
 has returned.
 If
 .Fa uc_link
-is a null pointer, then the context is the main context,
+is a
+.Dv NULL
+pointer, then the context is the main context,
 and the process will exit with an exit status of 0 upon return.
 .Pp
 The