1 files changed, 39 insertions, 0 deletions
diff --git a/winsup/cygwin/ipc.cc b/winsup/cygwin/ipc.cc
new file mode 100644
index 000000000..192a124d5
--- /dev/null
+++ b/winsup/cygwin/ipc.cc
@@ -0,0 +1,39 @@
+/* ipc.cc: Single unix specification IPC interface for Cygwin
+
+   Copyright 2001 Red Hat, Inc.
+
+   Originally written by Robert Collins <robert.collins@hotmail.com>
+
+   This file is part of Cygwin.
+
+   This software is a copyrighted work licensed under the terms of the
+   Cygwin license.  Please consult the file "CYGWIN_LICENSE" for
+   details. */
+
+#include "winsup.h"
+#include <sys/ipc.h>
+#include <sys/stat.h>
+
+extern "C"
+{
+
+/* Notes: we return a valid key even if id's low order 8 bits are 0. */
+key_t
+ftok(const char *path, int id)
+{
+  struct stat statbuf;
+  if (stat(path, &statbuf))
+    {
+      /* stat set the appropriate errno for us */
+      return (key_t) -1;
+    }
+  
+  /* dev_t is short for cygwin 
+   * ino_t is long for cygwin
+   * and we need 8 bits for the id.
+   * thus key_t is long long. 
+   */
+  return ((long long) statbuf.st_dev << (5*8)) | (statbuf.st_ino << (8) ) | (id & 0x00ff);
+}
+
+}