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[PATCH] manual: _Bool has trap representations
- From: Florian Weimer <fweimer at redhat dot com>
- To: GCC Patches <gcc-patches at gcc dot gnu dot org>
- Date: Mon, 19 Sep 2016 09:59:08 +0200
- Subject: [PATCH] manual: _Bool has trap representations
- Authentication-results: sourceware.org; auth=none
Defined behavior for extraordinary values of _Bool would be preferable,
but we can at least document what we have now.
Thanks,
Florian
2016-09-19 Florian Weimer <fweimer@redhat.com>
* doc/implement-c.texi (Integers implementation): _Bool has trap
representations.
Index: gcc/doc/implement-c.texi
===================================================================
--- gcc/doc/implement-c.texi (revision 240228)
+++ gcc/doc/implement-c.texi (working copy)
@@ -239,9 +239,13 @@
two's complement, or one's complement, and whether the extraordinary value
is a trap representation or an ordinary value (C99 and C11 6.2.6.2).}
-GCC supports only two's complement integer types, and all bit patterns
-are ordinary values.
+The standard integer types except @code{_Bool} are represented in two's
+complement, and all bit patterns are ordinary values.
+Ordinary values of @code{_Bool} are stored in memory as bytes with
+values 0 or 1. Other byte values are trap representations of the
+@code{_Bool} type.
+
@item
@cite{The rank of any extended integer type relative to another extended
integer type with the same precision (C99 and C11 6.3.1.1).}