1 files changed, 6 insertions, 0 deletions
diff --git a/Python/dup2.c b/Python/dup2.c
index 7c6bbfce11..a1df049209 100644
--- a/Python/dup2.c
+++ b/Python/dup2.c
@@ -11,6 +11,7 @@
  * Return fd2 if all went well; return BADEXIT otherwise.
  */
 
+#include <errno.h>
 #include <fcntl.h>
 #include <unistd.h>
 
@@ -20,12 +21,17 @@ int
 dup2(int fd1, int fd2)
 {
     if (fd1 != fd2) {
+#ifdef F_DUPFD
         if (fcntl(fd1, F_GETFL) < 0)
             return BADEXIT;
         if (fcntl(fd2, F_GETFL) >= 0)
             close(fd2);
         if (fcntl(fd1, F_DUPFD, fd2) < 0)
             return BADEXIT;
+#else
+        errno = ENOTSUP;
+        return BADEXIT;
+#endif
     }
     return fd2;
 }