1 files changed, 8 insertions, 3 deletions
diff --git a/lib/libc/stdio/putc.c b/lib/libc/stdio/putc.c
index fe1591c0dec4..72d6bbff12d8 100644
--- a/lib/libc/stdio/putc.c
+++ b/lib/libc/stdio/putc.c
@@ -42,14 +42,19 @@ static const char rcsid[] =
   "$FreeBSD$";
 #endif /* LIBC_SCCS and not lint */
 
+#include "namespace.h"
 #include <stdio.h>
+#include "un-namespace.h"
 #include "libc_private.h"
 
 /*
- * A subroutine version of the macro putc.
+ * putc has traditionally been a macro in <stdio.h>.  That is no
+ * longer true because POSIX requires it to be thread-safe.  POSIX
+ * does define putc_unlocked() which is defined as a macro and is
+ * probably what you want to use instead.
+ *
+ * #undef putc
  */
-#undef putc
-
 int
 putc(c, fp)
 	int c;