diff --git a/llvm/lib/Support/Unix/Process.inc b/llvm/lib/Support/Unix/Process.inc
index db735b7484ad8..c6e79af44b9b4 100644
--- a/llvm/lib/Support/Unix/Process.inc
+++ b/llvm/lib/Support/Unix/Process.inc
@@ -320,7 +320,7 @@ static unsigned getColumns(int FileID) {
   // instead if it isn't available.
   unsigned Columns = 0;
 
-#ifdef HAVE_SYS_IOCTL_H
+#if defined(HAVE_SYS_IOCTL_H) && !defined(__sun__)
   struct winsize ws;
   if (ioctl(FileID, TIOCGWINSZ, &ws) == 0)
     Columns = ws.ws_col;