New module 'link'.

[gnulib.git] / lib / unistd.in.h

diff --git a/lib/unistd.in.h b/lib/unistd.in.h
index fa8616a..52db71c 100644 (file)
--- a/lib/unistd.in.h
+++ b/lib/unistd.in.h
@@ -1,5 +1,5 @@
 /* Substitute for and wrapper around <unistd.h>.
-   Copyright (C) 2003-2008 Free Software Foundation, Inc.
+   Copyright (C) 2003-2009 Free Software Foundation, Inc.
 
    This program is free software; you can redistribute it and/or modify
    it under the terms of the GNU General Public License as published by
@@ -35,6 +35,7 @@
 #endif
 
 /* mingw fails to declare _exit in <unistd.h>.  */
+/* mingw, BeOS, Haiku declare environ in <stdlib.h>, not in <unistd.h>.  */
 #include <stdlib.h>
 
 #if @GNULIB_WRITE@ && @REPLACE_WRITE@ && @GNULIB_UNISTD_H_SIGPIPE@
@@ -474,6 +475,23 @@ extern int lchown (char const *file, uid_t owner, gid_t group);
 #endif
 
 
+#if @GNULIB_LINK@
+/* Create a new hard link for an existing file.
+   Return 0 if successful, otherwise -1 and errno set.
+   See POSIX:2001 specification
+   <http://www.opengroup.org/susv3xsh/link.html>.  */
+# if !@HAVE_LINK@
+extern int link (const char *path1, const char *path2);
+# endif
+#elif defined GNULIB_POSIXCHECK
+# undef link
+# define link(path1,path2) \
+    (GL_LINK_WARNING ("link is unportable - " \
+                      "use gnulib module link for portability"), \
+     link (path1, path2))
+#endif
+
+
 #if @GNULIB_LSEEK@
 # if @REPLACE_LSEEK@
 /* Set the offset of FD relative to SEEK_SET, SEEK_CUR, or SEEK_END.