Filter command :!

If no range is given then stdin is passed through which allows
interactive usage as in

 :!ls -1 *.c | slmenu

For this to work the command needs to use stderr for its user
interface and write any data for vis to stdout.

1 files changed, 2 insertions, 0 deletions

diff --git a/editor.h b/editor.h
index 7104d01..d985755 100644
--- a/editor.h
+++ b/editor.h
@@ -2,6 +2,7 @@
 #define EDITOR_H
 
 #include <curses.h>
+#include <signal.h>
 #include <stddef.h>
 #include <stdbool.h>
 
@@ -244,6 +245,7 @@ struct Editor {
 	Mode *mode_prev;     /* previsouly active user mode */
 	Mode *mode_before_prompt; /* user mode which was active before entering prompt */
 	volatile bool running; /* exit main loop once this becomes false */
+	volatile sig_atomic_t cancel_filter; /* abort external command */
 };
 
 Editor *editor_new(Ui*);