https://viewsourcecode.org/snaptoken/kilo/03.rawInputAndOutput.html#w…

…indow-size-the-hard-way

kilo.c

@@ -4,6 +4,7 @@
 #include <errno.h>
 #include <stdio.h>
 #include <stdlib.h>
+#include <sys/ioctl.h>
 #include <termios.h>
 #include <unistd.h>
 
@@ -13,7 +14,13 @@
 
 /*** data ***/
 
-struct termios orig_termios;
+struct editorConfig {
+  int screenrows;
+  int screencols;
+  struct termios orig_termios;
+};
+
+struct editorConfig E;
 
 /*** terminal ***/
 
@@ -26,14 +33,15 @@ void die(const char *s) {
 }
 
 void disableRawMode() {
-  if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &orig_termios) == -1) die("tcsetattr");
+  if (tcsetattr(STDIN_FILENO, TCSAFLUSH, &E.orig_termios) == -1)
+    die("tcsetattr");
 }
 
 void enableRawMode() {
-  if (tcgetattr(STDERR_FILENO, &orig_termios) == -1) die("tcgetattr");
+  if (tcgetattr(STDERR_FILENO, &E.orig_termios) == -1) die("tcgetattr");
   atexit(disableRawMode);
 
-  struct termios raw = orig_termios;
+  struct termios raw = E.orig_termios;
   raw.c_iflag &= ~(BRKINT | ICRNL | INPCK | ISTRIP | IXON);
   raw.c_oflag &= ~(OPOST);
   raw.c_cflag |= ~(CS8);
@@ -53,6 +61,18 @@ char editorReadKey() {
   return c;
 }
 
+int getWindowSize(int *rows, int *cols) {
+  struct winsize ws;
+
+  if (ioctl(STDIN_FILENO, TIOCGWINSZ, &ws) == -1 || ws.ws_col == 0) {
+    return -1;
+  } else {
+    *cols = ws.ws_col;
+    *rows = ws.ws_row;
+    return 0;
+  }
+}
+
 /*** input ***/
 void editorProcessKeyPress() {
   char c = editorReadKey();
@@ -71,7 +91,7 @@ void editorProcessKeyPress() {
 
 void editorDrawRows() {
   int y;
-  for (y = 0; y < 24; y++) {
+  for (y = 0; y < E.screenrows; y++) {
     write(STDOUT_FILENO, "~\r\n", 3);
   }
 }
@@ -87,8 +107,13 @@ void editorRefreshScreen() {
 
 /*** init ***/
 
+void initEditor() {
+  if (getWindowSize(&E.screenrows, &E.screencols) == -1) die("getWindowSize");
+}
+
 int main() {
   enableRawMode();
+  initEditor();
 
   while (1) {
     editorRefreshScreen();