diff --git a/bar.go b/bar.go
index fea6f97..e094e78 100644
--- a/bar.go
+++ b/bar.go
@@ -330,10 +330,6 @@
 func (s *bState) draw(termWidth int, pSyncer, aSyncer *widthSyncer) io.Reader {
 	defer s.bufA.WriteByte('\n')
 
-	if termWidth <= 0 {
-		termWidth = s.width
-	}
-
 	if s.panicMsg != "" {
 		return strings.NewReader(fmt.Sprintf(fmt.Sprintf("%%.%ds\n", termWidth), s.panicMsg))
 	}
diff --git a/cwriter/writer.go b/cwriter/writer.go
index 050f93e..8caeae1 100644
--- a/cwriter/writer.go
+++ b/cwriter/writer.go
@@ -2,12 +2,19 @@
 
 import (
 	"bytes"
+	"errors"
 	"fmt"
 	"io"
+	"os"
+
+	isatty "github.com/mattn/go-isatty"
+	"golang.org/x/crypto/ssh/terminal"
 )
 
 // ESC is the ASCII code for escape character
 const ESC = 27
+
+var NotATTY = errors.New("not a terminal")
 
 var (
 	cursorUp           = fmt.Sprintf("%c[%dA", ESC, 1)
@@ -53,3 +60,13 @@
 func (w *Writer) ReadFrom(r io.Reader) (n int64, err error) {
 	return w.buf.ReadFrom(r)
 }
+
+func (w *Writer) GetWidth() (int, error) {
+	if f, ok := w.out.(*os.File); ok {
+		if isatty.IsTerminal(f.Fd()) {
+			tw, _, err := terminal.GetSize(int(f.Fd()))
+			return tw, err
+		}
+	}
+	return -1, NotATTY
+}
diff --git a/cwriter/writer_posix.go b/cwriter/writer_posix.go
index 7d5c1f7..05e31c4 100644
--- a/cwriter/writer_posix.go
+++ b/cwriter/writer_posix.go
@@ -5,22 +5,9 @@
 import (
 	"io"
 	"strings"
-	"syscall"
-	"unsafe"
 )
 
 func (w *Writer) clearLines() error {
 	_, err := io.WriteString(w.out, strings.Repeat(clearCursorAndLine, w.lineCount))
 	return err
 }
-
-// TermSize returns the dimensions of the given terminal.
-// the code is stolen from "golang.org/x/crypto/ssh/terminal"
-func TermSize() (width, height int, err error) {
-	var dimensions [4]uint16
-
-	if _, _, err := syscall.Syscall6(syscall.SYS_IOCTL, uintptr(syscall.Stdout), uintptr(syscall.TIOCGWINSZ), uintptr(unsafe.Pointer(&dimensions)), 0, 0, 0); err != 0 {
-		return -1, -1, err
-	}
-	return int(dimensions[1]), int(dimensions[0]), nil
-}
diff --git a/cwriter/writer_windows.go b/cwriter/writer_windows.go
index 951933d..dad7f50 100644
--- a/cwriter/writer_windows.go
+++ b/cwriter/writer_windows.go
@@ -75,14 +75,3 @@
 	}
 	return nil
 }
-
-// TermSize returns the dimensions of the given terminal.
-// the code is stolen from "golang.org/x/crypto/ssh/terminal"
-func TermSize() (width, height int, err error) {
-	var info consoleScreenBufferInfo
-	_, _, e := syscall.Syscall(procGetConsoleScreenBufferInfo.Addr(), 2, uintptr(syscall.Stdout), uintptr(unsafe.Pointer(&info)), 0)
-	if e != 0 {
-		return 0, 0, error(e)
-	}
-	return int(info.size.x), int(info.size.y), nil
-}
diff --git a/progress_posix.go b/progress_posix.go
index b40c670..71df100 100644
--- a/progress_posix.go
+++ b/progress_posix.go
@@ -7,8 +7,6 @@
 	"os/signal"
 	"syscall"
 	"time"
-
-	"github.com/vbauerster/mpb/cwriter"
 )
 
 func (p *Progress) serve(s *pState) {
@@ -39,7 +37,10 @@
 				numA = s.bHeap.maxNumA()
 				s.heapUpdated = false
 			}
-			tw, _, _ := cwriter.TermSize()
+			tw, err := s.cw.GetWidth()
+			if err != nil {
+				tw = s.width
+			}
 			s.render(tw, numP, numA)
 		case <-winch:
 			if s.heapUpdated {
@@ -47,7 +48,10 @@
 				numA = s.bHeap.maxNumA()
 				s.heapUpdated = false
 			}
-			tw, _, _ := cwriter.TermSize()
+			tw, err := s.cw.GetWidth()
+			if err != nil {
+				tw = s.width
+			}
 			s.render(tw-tw/8, numP, numA)
 			if timer != nil && timer.Reset(resumeDelay) {
 				break
diff --git a/progress_windows.go b/progress_windows.go
index 65cbfd8..81f324f 100644
--- a/progress_windows.go
+++ b/progress_windows.go
@@ -1,10 +1,6 @@
 // +build windows
 
 package mpb
-
-import (
-	"github.com/vbauerster/mpb/cwriter"
-)
 
 func (p *Progress) serve(s *pState) {
 	var numP, numA int
@@ -26,7 +22,10 @@
 				numA = s.bHeap.maxNumA()
 				s.heapUpdated = false
 			}
-			tw, _, _ := cwriter.TermSize()
+			tw, err := s.cw.GetWidth()
+			if err != nil {
+				tw = s.width
+			}
 			s.render(tw, numP, numA)
 		}
 	}