[U-Boot] [PATCH] Introduce a global bool type

York Sun yorksun at freescale.com
Tue Jan 8 20:56:17 CET 2013


On 01/08/2013 11:07 AM, Wolfgang Denk wrote:
> Dear Timur Tabi,
> 
> In message <50EC5D29.1070408 at freescale.com> you wrote:
>>
>>> _Bool has been introduced very late to any C standard, and you can
>>> still see this from the ugly, unnatural name.
>>
>> It was introduced in C99, which is over 12 years old.
> 
> And how old is C?   I think the "official" announcment was 1972, so
> that's more than twice as long without that addition.
> 
>>> work wit than a CLI.  And I've seen more than one case where bugs were
>>> caused by using "proper bool types" like this:
>>>
>>> 	i = 0;
>>> 	j = 0;
>>> 	k = 2;
>>>
>>> 	if ((i | j | k) == true) ...
>>
>> Ok, but this is just wrong.  i, j, and k are not boolean types, so they
>> should not be compared with 'true' or 'false'.  I don't think you'll find
>> any disagreement with that.
> 
> You are right.  And I wrote that it's a bug.  But this is what you can
> easily get from using boolean types.  This is example has not been
> invented by me.  I don't even claim that this was good programming
> style - all I want to say is that from what I have seen the boolean
> types are not a panacea; they cause new problems as well.
> 

No disagree. How shall we close this? Will some change like below
acceptable?

diff --git a/include/linux/types.h b/include/linux/types.h
index 925ece7..f07ba41 100644
--- a/include/linux/types.h
+++ b/include/linux/types.h
@@ -7,6 +7,7 @@

 #include <linux/posix_types.h>
 #include <asm/types.h>
+#include <stdbool.h>

 #ifndef __KERNEL_STRICT_NAMES

@@ -113,10 +114,6 @@ typedef            __u64           u_int64_t;
 typedef                __s64           int64_t;
 #endif

-typedef _Bool bool;
-#define false 0
-#define true 1
-
 #endif /* __KERNEL_STRICT_NAMES */

 /*

York






More information about the U-Boot mailing list