From 4e516a1ee82e713c456b72f3f37dcddc7b69ad6c Mon Sep 17 00:00:00 2001
From: Mark Nudelman <markn@greenwoodsoftware.com>
Date: Fri, 4 Oct 2024 08:46:20 -0700
Subject: [PATCH] Add --no-poll option.

Related to #557.
---
 NEWS      |  2 ++
 opttbl.c  | 10 ++++++++++
 os.c      |  5 +++--
 version.c |  3 ++-
 4 files changed, 17 insertions(+), 3 deletions(-)

diff --git a/NEWS b/NEWS
index d6c8706b..35bc8f3f 100644
--- a/NEWS
+++ b/NEWS
@@ -21,6 +21,8 @@
 
 * Add --form-feed option (github #496).
 
+* Add --no-poll option (github #557).
+
 * Make TAB complete option name in -- command (github #531).
 
 * Make -R able to pass through any OSC escape sequences,
diff --git a/opttbl.c b/opttbl.c
index 3628449e..fdb2f6ca 100644
--- a/opttbl.c
+++ b/opttbl.c
@@ -84,6 +84,7 @@ public int match_shift;         /* Extra horizontal shift on search match */
 public int no_paste;            /* Don't accept pasted input */
 public int no_edit_warn;        /* Don't warn when editing a LESSOPENed file */
 public int stop_on_form_feed;   /* Stop scrolling on a line starting with form feed */
+public int no_poll;             /* Don't poll tty for ^X */
 public long match_shift_fraction = NUM_FRAC_DENOM/2; /* 1/2 of screen width */
 public char intr_char = CONTROL('X'); /* Char to interrupt reads */
 #if HILITE_SEARCH
@@ -184,6 +185,7 @@ static struct optname proc_backspace_optname = { "proc-backspace", NULL };
 static struct optname proc_tab_optname = { "proc-tab", NULL };
 static struct optname proc_return_optname = { "proc-return", NULL };
 static struct optname match_shift_optname = { "match-shift", NULL };
+static struct optname no_poll_optname = { "no-poll", NULL };
 #if LESSTEST
 static struct optname ttyin_name_optname = { "tty",              NULL };
 #endif /*LESSTEST*/
@@ -756,6 +758,14 @@ static struct loption option[] =
 			NULL
 		}
 	},
+	{ OLETTER_NONE, &no_poll_optname,
+		O_BOOL, OPT_OFF, &no_poll, NULL,
+		{
+			"Poll for ^X when reading data",
+			"Don't poll for ^X when reading data",
+			NULL
+		}
+	},
 #if LESSTEST
 	{ OLETTER_NONE, &ttyin_name_optname,
 		O_STRING|O_NO_TOGGLE, 0, NULL, opt_ttyin_name,
diff --git a/os.c b/os.c
index 9f897775..ec5bfaab 100644
--- a/os.c
+++ b/os.c
@@ -81,6 +81,7 @@ extern int follow_mode;
 extern int scanning_eof;
 extern char intr_char;
 extern int is_tty;
+extern int no_poll;
 #if !MSDOS_COMPILER
 extern int tty;
 #endif
@@ -152,7 +153,7 @@ public int supports_ctrl_x(void)
 	return (TRUE);
 #else
 #if USE_POLL
-	return (use_poll);
+	return (use_poll && !no_poll);
 #else
 	return (FALSE);
 #endif /* USE_POLL */
@@ -238,7 +239,7 @@ public ssize_t iread(int fd, unsigned char *buf, size_t len)
 	}
 #endif
 #if USE_POLL
-	if (is_tty && fd != tty && use_poll)
+	if (is_tty && fd != tty && use_poll && !no_poll)
 	{
 		int ret = check_poll(fd, tty);
 		if (ret != 0)
diff --git a/version.c b/version.c
index 08b54131..2dd909d2 100644
--- a/version.c
+++ b/version.c
@@ -1034,7 +1034,8 @@ v667  9/26/24   Fix uninitialized variable in edit_ifile.
 v659.1          Add --no-paste; add --no-edit-warn; add TAB for -- command;
                 add LESSANSIOSCALLOW and LESSANSIOSCCCHARS; fix bug searching 
                 near invalid UTF-8 sequence; add LESS_SHELL_LINES; fix bug 
-                with --no-number-headers; add mouse cmds to lesskey.
+                with --no-number-headers; add mouse cmds to lesskey;
+				add form-feed; add --no-poll.
 
 */