Index: safekill.c
==================================================================
--- safekill.c
+++ safekill.c
@@ -5,10 +5,11 @@
  * a utility to make it harder to accidentally nuke
  * important windows on i3wm or whatever. */
 
 #include <X11/Xlib.h>
 #include <X11/Xutil.h>
+#include <X11/Xatom.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <errno.h>
 typedef enum { false, true } bool;
@@ -21,12 +22,38 @@
 			if (str[1] == 'V' && str[2] == '}')
 				return str;
 			else { ++str; goto start; }
 		}
 }
+
+Display *display;
+
+void killwin(Window w) {
+	XEvent ev;
+	long mask = SubstructureRedirectMask | SubstructureNotifyMask;
+	ev.xclient.type       = ClientMessage;
+	ev.xclient.serial     = 0;
+	ev.xclient.send_event = True;
+	ev.xclient.message_type = XInternAtom(display, "_NET_CLOSE_WINDOW", False);
+	ev.xclient.window     = w;
+	ev.xclient.format     = 32;
+	
+	if(!XSendEvent(display, DefaultRootWindow(display), False, mask, &ev)) {
+		char* fallback = getenv("k_safekill_fallback");
+		bool nofb = (*fallback == '0' && fallback[1] == 0);
+
+		fprintf(stderr,"\x1b[1mwarning:\x1b[m cannot send _NET_CLOSE_WINDOW event to root window; is your window manager okay?");
+
+		if (nofb) {
+			fprintf(stderr,"\n");
+		} else {
+			fprintf(stderr," falling back to XDestroyWindow, but this may wreck your shit - lots of multi-win apps do *not* like it.\n");
+			XDestroyWindow(display,w);
+		}
+	}
+}
 int main(const int argc, const char** argv) {
-	Display *display;
 	Window focus;
 	int revert;
 
 	bool active;
 	enum { vitalize, devitalize, hardkill, softkill } op;
@@ -66,11 +93,11 @@
 		if (temp == 0) goto usage;
 		focus = (Window)temp;
 	}
 
 	if(op == hardkill) {
-		XDestroyWindow(display,focus);
+		killwin(focus);
 		XSync(display,false);
 		return 0;
 	}
 
 	XClassHint xclh;
@@ -82,11 +109,11 @@
 			else if (op == devitalize) {
 				strcpy(v, v+3);
 				XSetClassHint(display,focus,&xclh);
 				XSync(display,false);
 			} else if (op == softkill) {
-				printf("softkill forbidden\n");
+				fprintf(stderr, "softkill forbidden\n");
 				return 1; // ACCESS DENIED
 			}
 		} else {
 			if (op == vitalize) {
 				size_t sz=strlen(xclh.res_class); // TODO: remove double-walk
@@ -98,17 +125,17 @@
 				XSetClassHint(display,focus,&xclh);
 				XSync(display,false);
 			} else if (op == devitalize) return 0;
 			else if (op == softkill) {
 				// ice that motherfucker
-				XDestroyWindow(display,focus);
+				killwin(focus);
 				XSync(display,false);
 				return 3;
 			}
 		}
 	} else {
-		printf("\x1b[1merror:\x1b[m bad window\n");
+		fprintf(stderr,"\x1b[1merror:\x1b[m bad window\n");
 		goto usage;
 	}
 
 	return 0;
 
@@ -116,12 +143,12 @@
 	#define info  "\x1b[34m-- "
 	#define param "\x1b[32m"
 	#define eol   "\x1b[m\n"
 	#define bold  "\x1b[1m"
 	#define nl    "       "
-	printf(bold "usage:\x1b[0m %s    "       "     " info "kill active window if non-vital" eol
+	fprintf(stderr, bold "usage:\x1b[0m %s    "       "     " info "kill active window if non-vital" eol
 						 nl "%1$s -v " param "[id] " info "make [id] or active window vital" eol
 						 nl "%1$s -c " param "[id] " info "clear vital flag on [id] or active window" eol
 						 nl "%1$s -q " param "[id] " info "'emergency' kill w/o reference to vital flag" eol,
 				argv[0]);
 	return 1;
 }