[email protected] wrote:
A first step to a generic boolean-type. The patch just introduce the bool (in
Since gcc supports boolean types and can optimize for such, introducing
bool is IMO a good thing.
-Why would we want it?
-There is already some how are depending on a "boolean"-type (like NTFS). Also,
it will clearify functions who returns a boolean from one returning a value, ex:
bool it_is_ok();
char it_is_ok();
The first one is obvious what it is doing, the secound might return some sort of
status.
A better reason is that there is intrinsic compiler support for booleans.
-Why false and not FALSE, why not "enum {...} bool"
-They are not #define(d) and shouldn't because it is a value, like 'a'. But
because it is just a value, then bool is just a variable and should be able to
handle 0 and 1 equally well.
Well, this is _my_ opinion, it may be totally wrong. If so, please tell me ;)
Yes, I know about Andrew's try to unify TRUE and FALSE, did read the thread with
interest (that's from where I got to know about _Bool). But mostly (then still
on the subject) was some people did not want FALSE and TRUE instead of 0 and 1.
I look at it as: 'a' = 97, if someone like to write 97 instead of 'a', please do
if you find it easier to read. I, on the other hand, think it is easier with
'a', false/FALSE, NULL, etc.
We should follow what C99 directs.
diff --git a/include/asm-i386/types.h b/include/asm-i386/types.h
index 4b4b295..e35709a 100644
--- a/include/asm-i386/types.h
+++ b/include/asm-i386/types.h
@@ -10,6 +10,15 @@ typedef unsigned short umode_t;
* header files exported to user space
*/
+#if defined(__GNUC__) && __GNUC__ >= 3
+typedef _Bool bool;
+#else
+#warning You compiler doesn't seem to support boolean types, will set 'bool' as
an 'unsigned char'
+typedef unsigned char bool;
+#endif
+
+typedef bool u2;
NAK. gcc >= 3 is required by now, AFAIK.
Also, you don't want to force 'unsigned char' on code, because often
code prefers a machine integer to something smaller than a machine integer.
diff --git a/include/linux/stddef.h b/include/linux/stddef.h
index b3a2cad..5e5c611 100644
--- a/include/linux/stddef.h
+++ b/include/linux/stddef.h
@@ -10,6 +10,8 @@ #else
#define NULL ((void *)0)
#endif
+enum { false = 0, true = 1 } __attribute__((packed));
How is 'packed' attribute useful here?
Jeff
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