From 5d861a3399d7757c63dfda58c9daa1c9f442f391 Mon Sep 17 00:00:00 2001
From: ceriel <none@none>
Date: Mon, 15 Feb 1988 18:08:46 +0000
Subject: [PATCH] made to work

---
 lang/occam/lib/channel.c  | 30 +++++++++++++++++++++++++++++-
 lang/occam/lib/par_misc.e |  4 ++++
 2 files changed, 33 insertions(+), 1 deletion(-)

diff --git a/lang/occam/lib/channel.c b/lang/occam/lib/channel.c
index e66aabbe6..161c81e42 100644
--- a/lang/occam/lib/channel.c
+++ b/lang/occam/lib/channel.c
@@ -116,6 +116,13 @@ static int timeout();
 
 int chan_any(c) register chan *c;
 {
+#ifdef __BSD4_2
+#include <fcntl.h>
+#ifndef O_NDELAY
+#define O_NDELAY FNDELAY
+#endif
+	int flags;
+#endif
 	switch (c->type) {
 	case C_T_FILE:
 		if ((c->f.flgs&C_F_READAHEAD)!=0)
@@ -132,6 +139,24 @@ int chan_any(c) register chan *c;
 				deadlock=0;
 					/* No deadlock while waiting for key */
 
+				/* Unfortunately, the mechanism that was used
+				   here does not work on all Unix systems.
+				   On BSD 4.2 and newer, the "read" is 
+				   automatically restarted. Therefore, on
+				   these systems, we try it with non-blocking
+				   reads
+				*/
+#ifdef __BSD4_2
+				flags = fcntl(fileno(fp), F_GETFL, 0);
+				fcntl(fileno(fp), F_SETFL, flags | O_NDELAY);
+				errno = 0;
+				ch = getc(fp);
+				fcntl(fileno(fp), F_SETFL, flags);
+				if (errno == EWOULDBLOCK) {
+					clearerr(fp);
+					return 0;
+				}
+#else
 				signal(SIGALRM, timeout);
 				alarm(1);
 
@@ -141,8 +166,11 @@ int chan_any(c) register chan *c;
 				signal(SIGALRM, SIG_IGN);
 				alarm(0);
 
-				if (errno==EINTR)
+				if (errno==EINTR) {
+					clearerr(fp);
 					return 0;
+				}
+#endif
 				else {
 					if (!feof(fp)) {
 						c->f.flgs|=C_F_READAHEAD;
diff --git a/lang/occam/lib/par_misc.e b/lang/occam/lib/par_misc.e
index d96bc67cb..5ddc02d2e 100644
--- a/lang/occam/lib/par_misc.e
+++ b/lang/occam/lib/par_misc.e
@@ -12,6 +12,7 @@
 
  exp $top_save
  pro $top_save, 0
+ mes 11
  loe 0
  lae 4			; load line number and file name
  loi EM_PSIZE
@@ -37,11 +38,14 @@
 
  exp $top_load
  pro $top_load, 0
+ mes 11
  lal 0
  loi EM_PSIZE
  dup EM_PSIZE
  loi EM_PSIZE
  sti EM_PSIZE		; copy pointer from argument 0 to new frame
+ lal 0
+ loi EM_PSIZE
  loi EM_PSIZE		; load indirect to
  str 1			; restore SP
  dup EM_PSIZE		; givesargument 0 again
-- 
2.34.1