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authorJoseph Myers <joseph@codesourcery.com>2013-01-23 00:42:51 +0000
committerJoseph Myers <joseph@codesourcery.com>2013-01-23 00:42:51 +0000
commit052aff95782fefe9c63566471063e8b20836bfb8 (patch)
tree5d4216a958b589af26052cd6e97daf2a121bdab3 /bits
parent7c1e01aabcec96173b6e276e67322125ec90dff7 (diff)
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Make bits/wchar.h correct for all architectures (bug 15036).
Diffstat (limited to 'bits')
-rw-r--r--bits/wchar.h28
1 files changed, 26 insertions, 2 deletions
diff --git a/bits/wchar.h b/bits/wchar.h
index eb07151152..ef93d0e784 100644
--- a/bits/wchar.h
+++ b/bits/wchar.h
@@ -19,7 +19,31 @@
#ifndef _BITS_WCHAR_H
#define _BITS_WCHAR_H 1
-#define __WCHAR_MIN (-2147483647 - 1)
-#define __WCHAR_MAX (2147483647)
+/* The fallback definitions, for when __WCHAR_MAX__ or __WCHAR_MIN__
+ are not defined, give the right value and type as long as both int
+ and wchar_t are 32-bit types. Adding L'\0' to a constant value
+ ensures that the type is correct; it is necessary to use (L'\0' +
+ 0) rather than just L'\0' so that the type in C++ is the promoted
+ version of wchar_t rather than the distinct wchar_t type itself.
+ Because wchar_t in preprocessor #if expressions is treated as
+ intmax_t or uintmax_t, the expression (L'\0' - 1) would have the
+ wrong value for WCHAR_MAX in such expressions and so cannot be used
+ to define __WCHAR_MAX in the unsigned case. */
+
+#ifdef __WCHAR_MAX__
+# define __WCHAR_MAX __WCHAR_MAX__
+#elif L'\0' - 1 > 0
+# define __WCHAR_MAX (0xffffffffu + L'\0')
+#else
+# define __WCHAR_MAX (0x7fffffff + L'\0')
+#endif
+
+#ifdef __WCHAR_MIN__
+# define __WCHAR_MIN __WCHAR_MIN__
+#elif L'\0' - 1 > 0
+# define __WCHAR_MIN (L'\0' + 0)
+#else
+# define __WCHAR_MIN (-__WCHAR_MAX - 1)
+#endif
#endif /* bits/wchar.h */