X-Git-Url: https://git.distorted.org.uk/~mdw/sgt/putty/blobdiff_plain/a4451dd11df30dc2d0d262dd6c36642aa2a02b91..cbe80b7552d1012f023f702fe3ca31750047f362:/unix/uxpty.c

diff --git a/unix/uxpty.c b/unix/uxpty.c
index 60dc7f7d..ca7e98ad 100644
--- a/unix/uxpty.c
+++ b/unix/uxpty.c
@@ -360,8 +360,10 @@ static void pty_open_master(Pty pty)
         /*
          * Set the pty master into non-blocking mode.
          */
-        int i = 1;
-        ioctl(pty->master_fd, FIONBIO, &i);
+        int fl;
+	fl = fcntl(pty->master_fd, F_GETFL);
+	if (fl != -1 && !(fl & O_NONBLOCK))
+	    fcntl(pty->master_fd, F_SETFL, fl | O_NONBLOCK);
     }
 
     if (!ptys_by_fd)