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-rw-r--r--bits/errno.h44
1 files changed, 30 insertions, 14 deletions
diff --git a/bits/errno.h b/bits/errno.h
index 5a6a6dbb26..36c09f3f3c 100644
--- a/bits/errno.h
+++ b/bits/errno.h
@@ -1,4 +1,5 @@
-/* Copyright (C) 1991-2016 Free Software Foundation, Inc.
+/* Error constants. Generic version.
+ Copyright (C) 1991-2018 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
@@ -15,20 +16,35 @@
License along with the GNU C Library; if not, see
<http://www.gnu.org/licenses/>. */
-/* This file defines the `errno' constants. */
+/* This file defines the errno constants. */
-#if !defined __Emath_defined && (defined _ERRNO_H || defined __need_Emath)
-#undef __need_Emath
-#define __Emath_defined 1
+#ifndef _BITS_ERRNO_H
+#define _BITS_ERRNO_H 1
-# define EDOM XXX <--- fill in what is actually needed
-# define EILSEQ XXX <--- fill in what is actually needed
-# define ERANGE XXX <--- fill in what is actually needed
+#if !defined _ERRNO_H
+# error "Never include <bits/errno.h> directly; use <errno.h> instead."
#endif
-#ifdef _ERRNO_H
-# error "Define here all the missing error messages for the port. These"
-# error "must match the numbers of the kernel."
-# define Exxxx XXX
-...
-#endif
+#error "Generic bits/errno.h included -- port is incomplete."
+
+/* Authors of new ports of the GNU C Library must override this file
+ with their own bits/errno.h in an appropriate subdirectory of
+ sysdeps/. Its function is to define all of the error constants
+ from C2011 and POSIX.1-2008, with values appropriate to the
+ operating system, and any additional OS-specific error constants.
+
+ C2011 requires all error constants to be object-like macros that
+ expand to "integer constant expressions with type int, positive
+ values, and suitable for use in #if directives". Moreover, all of
+ their names must begin with a capital E, followed immediately by
+ either another capital letter, or a digit. It is OK to define
+ macros that are not error constants, but only in the implementation
+ namespace.
+
+ errno.h is sometimes included from assembly language. Therefore,
+ when __ASSEMBLER__ is defined, bits/errno.h may only define macros;
+ it may not make any other kind of C declaration or definition.
+ Also, the error constants should, if at all possible, expand to
+ simple decimal or hexadecimal numbers. */
+
+#endif /* bits/errno.h. */