next: https://viewsourcecode.org/snaptoken/kilo/05.aTextEditor.html

kilo.c

@@ -6,11 +6,13 @@
 
 #include <ctype.h>
 #include <errno.h>
+#include <time.h>
 #include <stdio.h>
 #include <stdlib.h>
 #include <string.h>
 #include <sys/ioctl.h>
 #include <sys/types.h>
+#include <stdarg.h>
 #include <termios.h>
 #include <unistd.h>
 
@@ -52,6 +54,8 @@ struct editorConfig {
   int numrows;
   erow *row;
   char *filename;
+  char statusmsg[80];
+  time_t statusmsg_time;
   struct termios orig_termios;
 };
 
@@ -434,6 +438,15 @@ void editorDrawStatusBar(struct abuf *ab) {
     }
   }
   abAppend(ab, "\x1b[m", 3);
+  abAppend(ab, "\r\n", 2);
+}
+
+void editorDrawMessageBar(struct abuf *ab) {
+  abAppend(ab, "\x1b[K", 3);
+  int msglen = strlen(E.statusmsg);
+  if (msglen > E.screencols) msglen = E.screencols;
+  if (msglen && time(NULL) - E.statusmsg_time < 5)
+    abAppend(ab, E.statusmsg, msglen);
 }
 
 void editorRefreshScreen() {
@@ -445,6 +458,7 @@ void editorRefreshScreen() {
 
   editorDrawRows(&ab);
   editorDrawStatusBar(&ab);
+  editorDrawMessageBar(&ab);
 
   char buf[32];
   snprintf(buf, sizeof(buf), "\x1b[%d;%dH", (E.cy - E.rowoff) + 1,
@@ -457,6 +471,14 @@ void editorRefreshScreen() {
   abFree(&ab);
 }
 
+void editorSetStatusMessage(const char *fmt, ...) {
+  va_list ap;
+  va_start(ap, fmt);
+  vsnprintf(E.statusmsg, sizeof(E.statusmsg), fmt, ap);
+  va_end(ap);
+  E.statusmsg_time = time(NULL);
+}
+
 /*** init ***/
 
 void initEditor() {
@@ -468,9 +490,11 @@ void initEditor() {
   E.numrows = 0;
   E.row = NULL;
   E.filename = NULL;
+  E.statusmsg[0] = '\0';
+  E.statusmsg_time = 0;
 
   if (getWindowSize(&E.screenrows, &E.screencols) == -1) die("getWindowSize");
-  E.screenrows -= 1;
+  E.screenrows -= 2;
 }
 
 int main(int argc, char *argv[]) {
@@ -480,6 +504,8 @@ int main(int argc, char *argv[]) {
     editorOpen(argv[1]);
   }
 
+  editorSetStatusMessage("HELP: Ctrl-Q = quit");
+
   while (1) {
     editorRefreshScreen();
     editorProcessKeyPress();