lynx-dev Problem with ^Z suspending: ncurses lib_tstp.pch

[Klaus Weide]

I made the following changes to some ncurses sources I had lying
around.  Sorry it's not the latest version, didn't want to download
the whole thing, this was version 4.0.

This works for me to solve problems I and III (see my other message,
http://www.flora.org/lynx-dev/html/month0199/msg00737.html).

Tom, can you look at this for including in ncurses?  I'm sure it needs
at least some ifdefs.

   Klaus

--- lib_tstp.c.old      Wed Jan 27 10:52:15 1999
+++ lib_tstp.c  Wed Jan 27 11:46:16 1999
@@ -95,13 +95,23 @@
 {
        sigset_t mask, omask;
        sigaction_t act, oact;
+       
+       int tty_stolen, sigttou_blocked;
 
        T(("tstp() called"));
 
        /*
         * The user may have changed the prog_mode tty bits, so save them.
+        *
+        * But first try to detect whether we still are in the foreground
+        * process group - if not, an interactive shell may already have
+        * taken ownership of the tty and modified the settings when our
+        * parent was stopped before us, and we would likely pick up the
+        * settings already modified by the shell.
         */
-       def_prog_mode();
+       tty_stolen = (tcgetpgrp(STDIN_FILENO) != getpgrp());
+       if (!tty_stolen)
+           def_prog_mode();
 
        /*
         * Block window change and timer signals.  The latter
@@ -115,6 +125,15 @@
 #endif
        (void)sigprocmask(SIG_BLOCK, &mask, &omask);
 
+#ifdef SIGTTOU
+       sigttou_blocked = sigismember(&omask, SIGTTOU);
+       if (!sigttou_blocked) {
+           (void)sigemptyset(&mask);
+           (void)sigaddset(&mask, SIGTTOU);
+           (void)sigprocmask(SIG_BLOCK, &mask, NULL);
+       }
+#endif
+
        /*
         * End window mode, which also resets the terminal state to the
         * original (pre-curses) modes.
@@ -124,6 +143,12 @@
        /* Unblock SIGTSTP. */
        (void)sigemptyset(&mask);
        (void)sigaddset(&mask, SIGTSTP);
+#ifdef SIGTTOU
+       if (!sigttou_blocked) {
+            /* Unblock this too if it wasn't blocked on entry */
+           (void)sigaddset(&mask, SIGTTOU);
+       }
+#endif
        (void)sigprocmask(SIG_UNBLOCK, &mask, NULL);
 
        /* Now we want to resend SIGSTP to this process and suspend it */