1 files changed, 37 insertions, 0 deletions
diff --git a/otherlibs/unix/dup2.c b/otherlibs/unix/dup2.c
new file mode 100644
index 000000000..e8fbc3647
--- /dev/null
+++ b/otherlibs/unix/dup2.c
@@ -0,0 +1,37 @@
+#include <mlvalues.h>
+#include "unix.h"
+
+#ifdef HAS_DUP2
+
+value unix_dup2(fd1, fd2)        /* ML */
+     value fd1, fd2;
+{
+  if (dup2(Int_val(fd1), Int_val(fd2)) == -1) uerror("dup2", Nothing);
+  return Val_unit;
+}
+
+#else
+
+static int do_dup2(fd1, fd2)
+     int fd1, fd2;
+{
+  int fd;
+  int res;
+
+  fd = dup(fd1);
+  if (fd == -1) return -1;
+  if (fd == fd2) return 0;
+  res = do_dup2(fd1, fd2);
+  close(fd);
+  return res;
+}
+
+value unix_dup2(fd1, fd2)        /* ML */
+     value fd1, fd2;
+{
+  close(Int_val(fd2));
+  if (do_dup2(Int_val(fd1), Int_val(fd2)) == -1) uerror("dup2", Nothing);
+  return Val_unit;
+}
+
+#endif