PATCH: ptyread eating CPU on Cygwin

["Andrej Borsenkow" <Andrej.Borsenkow@mow.siemens.ru>]

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>
> The problem I was having was with putting the terminal temporarily into raw
> mode without the full majesty of zle and setting a timeout there (in
> bin_read()).  select is working fine in the main terminal code.  I didn't
> have the week necessary to resolve all the possible ways of setting
> timeouts, so I gave up.  I expect it can be done.
>

O.K., this is very simple patch that makes ptyread use select. Sven, could you
look at conditions there? It should be O.K. (blocking select can return either
positive value or -1 if interrupted, in which case we simply exit read loop).

With this patch 'make check' has acceptable CPU load.

Attached due to line length.

-andrej

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Index: Src/Modules/zpty.c
===================================================================
RCS file: /cvsroot/zsh/zsh/Src/Modules/zpty.c,v
retrieving revision 1.11
diff -u -r1.11 zpty.c
--- Src/Modules/zpty.c	2000/06/27 14:25:05	1.11
+++ Src/Modules/zpty.c	2000/10/18 11:26:20
@@ -446,6 +446,9 @@
     int blen = 256, used = 0, ret = 1;
     char *buf = (char *) zhalloc(blen + 1);
     Patprog prog = NULL;
+#ifdef HAVE_SELECT
+    fd_set foofd;
+#endif
 
     if (*args && args[1]) {
 	char *p;
@@ -468,7 +471,16 @@
 	    if (cmd->fin)
 		break;
 	}
-	if ((ret = read(cmd->fd, buf + used, 1)) == 1) {
+#ifdef HAVE_SELECT
+        FD_ZERO(&foofd);
+        FD_SET(cmd->fd, &foofd);
+#endif
+        if (
+#ifdef HAVE_SELECT
+	    (ret = select(cmd->fd+1, (SELECT_ARG_2_T) &foofd, NULL, NULL, NULL) > 0) &&
+#endif
+
+	(ret = read(cmd->fd, buf + used, 1)) == 1) {
 	    if (++used == blen) {
 		buf = hrealloc(buf, blen, blen << 1);
 		blen <<= 1;