PATCH: Poll tty before selecting on Solaris

[Peter Stephenson <pws@xxxxxxx>]

This extravaganza is necessary on Solaris when you use select() with the
terminal and there is already typeahead --- it doesn't see it, you need
to use a read with the termios poll mechanism.  You wouldn't typically
see this unless you use the zle -F mechanism to wait for other output;
unfortunately I use this all day to talk to BlueCore.

If anyone can tell me what it is I'm doing wrong in order to avoid this,
that would be a relief.

Index: Src/Zle/zle_main.c
===================================================================
RCS file: /cvsroot/zsh/zsh/Src/Zle/zle_main.c,v
retrieving revision 1.29
diff -u -r1.29 zle_main.c
--- Src/Zle/zle_main.c	27 Jan 2003 14:54:53 -0000	1.29
+++ Src/Zle/zle_main.c	14 Feb 2003 18:51:13 -0000
@@ -348,13 +348,12 @@
 {
     long exp100ths;
     int ret;
+#ifdef HAS_TIO
+    struct ttyinfo ti;
+#endif
 #ifndef HAVE_POLL
 # ifdef HAVE_SELECT
     fd_set foofd;
-# else
-#  ifdef HAS_TIO
-    struct ttyinfo ti;
-#  endif
 # endif
 #endif
 
@@ -379,9 +378,40 @@
 	    int i, errtry = 0, selret;
 # ifdef HAVE_POLL
 	    int poll_timeout;
-	    int nfds = keytmout ? 1 : 1 + nwatch;
+	    int nfds;
+	    struct pollfd *fds;
+# else
+	    int fdmax;
+	    struct timeval *tvptr;
+	    struct timeval expire_tv;
+# endif
+# if defined(HAS_TIO) && defined(sun)
+	    /*
+	     * Yes, I know this is complicated.  Yes, I know we
+	     * already have three bits of code to poll the terminal
+	     * down below.  No, I don't want to do this either.
+	     * However, it turns out on certain OSes, specifically
+	     * Solaris, that you can't poll typeahead for love nor
+	     * money without actually trying to read it.  But
+	     * if we are trying to select (and we need to if we
+	     * are watching other fd's) we won't pick that up.
+	     * So we just try and read it without blocking in
+	     * the time-honoured (i.e. absurdly baroque) termios
+	     * fashion.
+	     */
+	    gettyinfo(&ti);
+	    ti.tio.c_cc[VMIN] = 0;
+	    settyinfo(&ti);
+	    ret = read(SHTTY, cptr, 1);
+	    ti.tio.c_cc[VMIN] = 1;
+	    settyinfo(&ti);
+	    if (ret > 0)
+		return 1;
+# endif
+# ifdef HAVE_POLL
+	    nfds = keytmout ? 1 : 1 + nwatch;
 	    /* First pollfd is SHTTY, following are the nwatch fds */
-	    struct pollfd *fds = zalloc(sizeof(struct pollfd) * nfds);
+	    fds = zalloc(sizeof(struct pollfd) * nfds);
 	    if (exp100ths)
 		poll_timeout = exp100ths * 10;
 	    else
@@ -400,9 +430,8 @@
 		}
 	    }
 # else
-	    int fdmax = SHTTY;
-	    struct timeval *tvptr = NULL;
-	    struct timeval expire_tv;
+	    fdmax = SHTTY;
+	    tvptr = NULL;
 	    if (exp100ths) {
 		expire_tv.tv_sec = exp100ths / 100;
 		expire_tv.tv_usec = (exp100ths % 100) * 10000L;

-- 
Peter Stephenson <pws@xxxxxxx>                  Software Engineer
CSR Ltd., Science Park, Milton Road,
Cambridge, CB4 0WH, UK                          Tel: +44 (0)1223 692070


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