Check return value from ioctl(TIOCGWINSZ)

Make sure the function succeeded before looking at the return value.

Signed-off-by: Keith Packard <keithp@keithp.com>

1 files changed, 1 insertions, 3 deletions

diff --git a/xprop.c b/xprop.c
index ec82257..8d60089 100644
--- a/xprop.c
+++ b/xprop.c
@@ -1946,9 +1946,7 @@ main (int argc, char **argv)
 #ifdef TIOCGWINSZ
     struct winsize ws;
     ws.ws_col = 0;
-    ioctl(STDIN_FILENO, TIOCGWINSZ, &ws);
-
-    if (ws.ws_col != 0)
+    if (ioctl(STDIN_FILENO, TIOCGWINSZ, &ws) != -1 && ws.ws_col != 0)
 	term_width = ws.ws_col;
 #endif