Take out my (long since disabled) POSIX signal mask handling code.

I'm not going to have the time or energy to get this working x-platform
-- anyone who does is welcome to the code!

2 files changed, 6 insertions, 54 deletions

diff --git a/Doc/lib/libsignal.tex b/Doc/lib/libsignal.tex
index 3029385..e3aa171 100644
--- a/Doc/lib/libsignal.tex
+++ b/Doc/lib/libsignal.tex
@@ -18,6 +18,10 @@ the handler for \constant{SIGCHLD}, which follows the underlying
 implementation.
 
 \item
+There is no way to ``block'' signals temporarily from critical
+sections (since this is not supported by all \UNIX{} flavors).
+
+\item
 Although Python signal handlers are called asynchronously as far as
 the Python user is concerned, they can only occur between the
 ``atomic'' instructions of the Python interpreter.  This means that
@@ -88,16 +92,6 @@ The variables defined in the \module{signal} module are:
   One more than the number of the highest signal number.
 \end{datadesc}
 
-\begin{datadesc}{SIG_BLOCK}
-\end{datadesc}
-\begin{datadesc}{SIG_UNBLOCK}
-\end{datadesc}
-\begin{datadesc}{SIG_SETMASK}
-  These constants are for use as the first parameter of the
-  \function{sigprocmask} function described below.
-\end{datadesc}
-
-
 The \module{signal} module defines the following functions:
 
 \begin{funcdesc}{alarm}{time}
@@ -150,46 +144,6 @@ The \module{signal} module defines the following functions:
 \obindex{frame}
 \end{funcdesc}
 
-The following functions are supported if your platform does.  Most
-modern \UNIX-alikes now do.
-
-\begin{funcdesc}{sigpending}{}
-  Return the set of pending signals, i.e. a list containing the
-  numbers of those signals that have been raised while blocked.
-  \versionadded{2.3}
-\end{funcdesc}
-
-\begin{funcdesc}{sigprocmask}{how, sigset}
-  Change the list of currently blocked signals.  The parameter
-  \var{how} should be one of \constant{SIG_BLOCK},
-  \constant{SIG_UNBLOCK} or \constant{SIG_SETMASK} and \var{sigset}
-  should be a sequence of signal numbers.  The behaviour of the call
-  depends on the value of \var{how}:
-
-  \begin{tableii}{l|l}{textrm}{Value of \var{how}}{Behaviour of call}
-    \lineii{\constant{SIG_BLOCK}}
-	   {The set of blocked signals is the union of the current set
-            and \var{sigset}.}
-    \lineii{\constant{SIG_UNBLOCK}}      
-           {The signals in \var{sigset} are removed from the current
-            set of blocked signals.  It is legal to attempt to unblock 
-            a signal which is not blocked.}
-    \lineii{\constant{SIG_SETMASK}}
-	   {The set of blocked signals is set to the \var{sigset}.}
-  \end{tableii}
-
-  A list contating the numbers of the previously blocked signals is
-  returned.
-  \versionadded{2.3}
-\end{funcdesc}
-
-\begin{funcdesc}{sigsuspend}{sigset}
-  Temporarily replace the signal mask with \var{sigset} (which should
-  be a sequnce of signal numbers) and suspend the process until a
-  signal is received.
-  \versionadded{2.3}
-\end{funcdesc}
-
 \subsection{Example}
 \nodename{Signal Example}
 
diff --git a/Doc/whatsnew/whatsnew23.tex b/Doc/whatsnew/whatsnew23.tex
index 362db5f..de46869 100644
--- a/Doc/whatsnew/whatsnew23.tex
+++ b/Doc/whatsnew/whatsnew23.tex
@@ -1485,10 +1485,8 @@ it immediately.)
 location.
 
 \item Support for more advanced POSIX signal handling was added
-to the \module{signal} module by adding the \function{sigpending},
-\function{sigprocmask} and \function{sigsuspend} functions where supported
-by the platform.  These functions make it possible to avoid some previously
-unavoidable race conditions with signal handling.
+to the \module{signal} but then removed again as it proved impossible
+to make it work reliably across platforms.
 
 \item The \module{socket} module now supports timeouts.  You
 can call the \method{settimeout(\var{t})} method on a socket object to