Update the current sigaction(2) man page to current reality..

* sigstack(2) -> sigaltstack(2).
* Document the SA_NODEFER flag
* Document the SA_RESETHAND flag

1 files changed, 19 insertions, 5 deletions

diff --git a/lib/libc/sys/sigaction.2 b/lib/libc/sys/sigaction.2
index 64f534d..b9fe5ca 100644
--- a/lib/libc/sys/sigaction.2
+++ b/lib/libc/sys/sigaction.2
@@ -50,7 +50,7 @@ struct sigaction {
 .Sh DESCRIPTION
 The system defines a set of signals that may be delivered to a process.
 Signal delivery resembles the occurrence of a hardware interrupt:
-the signal is blocked from further occurrence, the current process 
+the signal is normally blocked from further occurrence, the current process 
 context is saved, and a new one is built.  A process may specify a
 .Em handler
 to which a signal is delivered, or specify that a signal is to be 
@@ -68,7 +68,7 @@ of the process.  This may be changed, on a per-handler basis,
 so that signals are taken on a special
 .Em "signal stack" .
 .Pp
-Signal routines execute with the signal that caused their
+Signal routines normally execute with the signal that caused their
 invocation
 .Em blocked ,
 but other signals may yet occur.
@@ -131,7 +131,7 @@ If
 is non-zero, the previous handling information for the signal
 is returned to the user.
 .Pp
-Once a signal handler is installed, it remains installed
+Once a signal handler is installed, it normally remains installed
 until another
 .Fn sigaction
 call is made, or an 
@@ -178,7 +178,16 @@ bit is set in
 the system will deliver the signal to the process on a
 .Em "signal stack" ,
 specified with
-.Xr sigstack 2 .
+.Xr sigaltstack 2 .
+If the
+.Dv SA_NODEFER
+bit is set, further occurrences of the delivered signal are not
+masked during the execution of the handler.
+If the
+.Dv SA_RESETHAND
+bit is set, the handler is reset back to
+.Dv SIG_DFL
+at the moment the signal is delivered.
 .Pp
 If a signal is caught during the system calls listed below,
 the call may be forced to terminate
@@ -352,6 +361,11 @@ and
 Those signals are available on most
 .Tn BSD Ns \-derived
 systems.
+The
+.Dv SA_NODEFER
+and
+.Dv SA_RESETHAND
+are intended for backwards compatability with other operating systems.
 .Sh SEE ALSO
 .Xr kill 1 ,
 .Xr ptrace 2 ,
@@ -362,7 +376,7 @@ systems.
 .Xr sigblock 2 ,
 .Xr sigsetmask 2 ,
 .Xr sigpause 2 ,
-.Xr sigstack 2 ,
+.Xr sigaltstack 2 ,
 .Xr sigvec 2 ,
 .Xr setjmp 3 ,
 .Xr siginterrupt 3 ,