Paul Eggert wrote on 2010-08-24, in
<http://lists.gnu.org/archive/html/bug-gnulib/2010-08/msg00170.html>:
> the C standard
> says that "&s" is a valid static initializer, but I suppose
> one could argue that there's an implicit conversion to bool that would
> clearly be invalid if one made it explicit and wrote "(bool) &s" there.
> ...
> --- a/lib/autoconf/headers.m4
> +++ b/lib/autoconf/headers.m4
> @@ -628,7 +628,7 @@ AC_DEFUN([AC_HEADER_STDBOOL],
> char b[false == 0 ? 1 : -1];
> char c[__bool_true_false_are_defined == 1 ? 1 : -1];
> char d[(bool) 0.5 == true ? 1 : -1];
> - bool e = &s;
> + /* See body of main program for 'e'. */
> char f[(_Bool) 0.0 == false ? 1 : -1];
> char g[true];
> char h[sizeof (_Bool)];
> @@ -666,6 +647,7 @@ AC_DEFUN([AC_HEADER_STDBOOL],
> _Bool *pq = &q;
> ]],
> [[
> + bool e = &s;
> *pq |= q;
> *pq |= ! q;
> /* Refer to every declared value, to avoid compiler optimizations. */
This issue occurs again with Compaq C V6.5-303 on OSF/1 5.1.
source='test-stdbool.c' object='test-stdbool.o' libtool=no DEPDIR=.deps
depmode=tru64 /bin/ksh ./../build-aux/depcomp cc -O -DHAVE_CONFIG_H -I.
-DGNULIB_STRICT_CHECKING=1 -I. -I. -I.. -I./.. -I../gllib -I./../gllib
-ieee -c -o test-stdbool.o test-stdbool.c
cc: Error: test-stdbool.c, line 65: In the initializer for e, the address
cannot be converted to the destination type. (badstaticcvt)
bool e = &s;
---------^
*** Exit 1
After the test in m4/stdbool.m4 has been relaxed, the unit test needs to be
relaxed accordingly. Here's the patch that I will push:
2010-12-19 Bruno Haible <br...@clisp.org>
stdbool: Relax test.
* tests/test-stdbool.c (e): Don't require that casts from a variable's
address to 'bool' work in static initializer, for compilers other than
GCC.
--- tests/test-stdbool.c.orig Sun Dec 19 15:24:10 2010
+++ tests/test-stdbool.c Sun Dec 19 15:23:08 2010
@@ -61,8 +61,13 @@
char c[__bool_true_false_are_defined == 1 ? 1 : -1];
#if HAVE_STDBOOL_H || defined __GNUC__ /* See above. */
char d[(bool) 0.5 == true ? 1 : -1];
-# ifdef ADDRESS_CHECK_OKAY
+# ifdef ADDRESS_CHECK_OKAY /* Avoid gcc warning. */
+/* C99 may plausibly be interpreted as not requiring support for a cast from
+ a variable's address to bool in a static initializer. So treat it like a
+ GCC extension. */
+# ifdef __GNUC__
bool e = &s;
+# endif
# endif
char f[(_Bool) 0.0 == false ? 1 : -1];
#endif
@@ -85,6 +90,13 @@
int
main ()
{
+#if HAVE_STDBOOL_H || defined __GNUC__ /* See above. */
+# ifdef ADDRESS_CHECK_OKAY /* Avoid gcc warning. */
+ /* A cast from a variable's address to bool is valid in expressions. */
+ bool e1 = &s;
+# endif
+#endif
+
/* Catch a bug in IBM AIX xlc compiler version 6.0.0.0
reported by James Lemley on 2005-10-05; see
http://lists.gnu.org/archive/html/bug-coreutils/2005-10/msg00086.html
