diff --git a/sysdeps/mach/hurd/bits/posix_opt.h b/sysdeps/mach/hurd/bits/posix_opt.h
index b7f80e32e1..2da2921bf5 100644
--- a/sysdeps/mach/hurd/bits/posix_opt.h
+++ b/sysdeps/mach/hurd/bits/posix_opt.h
@@ -53,7 +53,7 @@
 
 /* Elements of the `c_cc' member of `struct termios' structure
    can be disabled by using the value _POSIX_VDISABLE.  */
-#define _POSIX_VDISABLE			'\0'
+#define _POSIX_VDISABLE			0
 
 
 /* Different Hurd filesystems might do these differently.
diff --git a/sysdeps/unix/sysv/linux/bits/posix_opt.h b/sysdeps/unix/sysv/linux/bits/posix_opt.h
index 60ab46a575..d55f907b0f 100644
--- a/sysdeps/unix/sysv/linux/bits/posix_opt.h
+++ b/sysdeps/unix/sysv/linux/bits/posix_opt.h
@@ -54,7 +54,7 @@
 
 /* `c_cc' member of 'struct termios' structure can be disabled by
    using the value _POSIX_VDISABLE.  */
-#define	_POSIX_VDISABLE	'\0'
+#define	_POSIX_VDISABLE	0
 
 /* Filenames are not silently truncated.  */
 #define	_POSIX_NO_TRUNC	1