[cfe-dev] [libcxx]: a testsuite bug involving boolean type and values

[ZhangXiongpang]

Jordan Rose wrote
> Hello, Xiongpang. Notice that this particular test case is compiled as
> C++. In C++, 
> <stdbool.h>
>  does not actually have to do anything. From C++11 [support.runtime]p8:
> "The header 
> <cstdbool>
>  and the header 
> <stdbool.h>
>  shall not define macros named bool, true, or false."
> 
> For C, of course, the header must define the four macros.
> 
> Best,
> Jordan
> 
> 
> On Oct 9, 2012, at 22:53 , ZhangXiongpang <

> zhangxiongpang@

> > wrote:
> 
>> I saw the code in
>>    test/depr/depr.c.headers/stdbool_h.pass.cpp
>> as follows:
>> --------------------------------------------------
>> #include 
> <stdbool.h>
>> 
>> #ifndef __bool_true_false_are_defined
>> #error __bool_true_false_are_defined not defined
>> #endif
>> 
>> #ifdef bool // why bool should not be defined?
>> #error bool should not be defined
>> #endif
>> 
>> #ifdef true // idem
>> #error true should not be defined
>> #endif
>> 
>> #ifdef false // idem
>> #error false should not be defined
>> #endif
>> --------------------------------------------------
>> 
>> Why bool/true/false should not be defined?
>> Is it a bug of the stdbool_h.pass.cpp?
>> I think it should be:
>> --------------------------------------------------
>> #ifndef bool
>> #error bool should not defined
>> #endif
>> 
>> #ifndef true
>> #error true should not defined
>> #endif
>> 
>> #ifndef false
>> #error false should not defined
>> #endif
>> --------------------------------------------------
>> 
>> Because the section 7.18 of  n1548.pdf
>> <http://www.open-std.org/jtc1/sc22/wg14/www/docs/n1548.pdf>   says:
>> --------------------------------------------------
>> 7.18 Boolean type and values 
> <stdbool.h>
>> 1 The header 
> <stdbool.h>
>  defines four macros.
>> 2 The macro bool expands to _Bool.
>> 3 The remaining three macros are suitable for use in #if preprocessing
>> directives. They are true which expands to the integer constant 1, false
>> which expands to the integer constant 0, and _bool_true_false_are_defined
>> which expands to the integer constant 1.
>> --------------------------------------------------
>> 
>> 
>> 
>> --
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Thanks Jordan!

Zhang Xiongpang



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