Clang to Tidy the use of a signed integer operand with a binary bitwise operator-CodePudding

I use C on CLion implements a sequence table, at the time of expansion, I choose expansion for the original 1.5 times, as shown in figure code, I operated by displacement when the compiler will report a warning, warning the baidu, Google is to look not to understand, that also please the great god inspiration. Thank you!

CodePudding user response:

This warning is for a signed do a bitwise operations, the size should be symbolic variable, if will try unsigned variable size programming, a signed integer programming unsigned integer,

CodePudding user response:

reference 1st floor cfjtaishan response:

this warning is for a number of symbols do bitwise operations, the size should be a symbolic variable, if will try unsigned variable size programming, a signed integer programming unsigned integer,

Just tried to unsigned will also have this warning,, and I don't usually unsigned, calculation may have a problem with the words,,
Don't have C symbol digital shift will have a problem?

CodePudding user response:

refer to the second floor SinY_Chan response:

Quote: refer to 1st floor cfjtaishan response:

This warning is to have a number of symbols do bitwise operations, the size should be a symbolic variable, if will try unsigned variable size programming, a signed integer programming unsigned integer,

Just tried to unsigned will also have this warning,, and I don't usually unsigned, calculation may have a problem with the words,,
Don't have C symbol digital shift will have a problem?

The proposal does not use shift operation, and use division, namely p - & gt; The size/2 + 1;

CodePudding user response:

reference cfjtaishan reply: 3/f

Quote: refer to the second floor SinY_Chan response:

Quote: refer to 1st floor cfjtaishan response:

This warning is to have a number of symbols do bitwise operations, the size should be a symbolic variable, if will try unsigned variable size programming, a signed integer programming unsigned integer,

Just tried to unsigned will also have this warning,, and I don't usually unsigned, calculation may have a problem with the words,,
Don't have C symbol digital shift will have a problem?

The proposal does not use shift operation, and use division, namely p - & gt; The size/2 + 1;

Well? I'm into this kind of writing, because I think using displacement operation would be faster,, so just wrote, but feel nothing but give me warning, have questions, or thank you

CodePudding user response:

Fyi:

 # include & lt; stdio.h> 
Unsigned short int UI; 
Signed short int si; 
Int main () {
UI=(unsigned short int) 0 x8000u; 
Si=(signed short int) 0 x8000; 
Printf (" UI=% u \ n ", UI); 
Printf (" si=% d \ n ", si); 
UI=ui> 1; 
Si=si> 1; 
Printf (" UI=% u \ n ", UI); 
Printf (" si=% d \ n ", si); 

Printf (" -- -- -- -- -- -- -- -- -- -- -- -- -- -- \ n "); 
UI=(unsigned short int) 0 x8000u; 
Si=(signed short int) 0 x8000; 
Printf (" UI=% u \ n ", UI); 
Printf (" si=% d \ n ", si); 
UI=((signed short int) UI) & gt;> 1; 
Si=((unsigned short int) si) & gt;> 1; 
Printf (" UI=% u \ n ", UI); 
Printf (" si=% d \ n ", si); 

return 0; 
} 
//UI=32768 
//si=- 32768 
//UI=16384 
//si=- 16384 
//-- -- -- -- -- -- -- -- -- -- -- -- -- -- 
//UI=32768 
//si=- 32768 
//UI=49152 
//si=16384

CodePudding user response:

reference 4 floor SinY_Chan response:

Quote: reference cfjtaishan reply: 3/f

Quote: refer to the second floor SinY_Chan response:

Quote: refer to 1st floor cfjtaishan response:

This warning is to have a number of symbols do bitwise operations, the size should be a symbolic variable, if will try unsigned variable size programming, a signed integer programming unsigned integer,

Just tried to unsigned will also have this warning,, and I don't usually unsigned, calculation may have a problem with the words,,
Don't have C symbol digital shift will have a problem?

The proposal does not use shift operation, and use division, namely p - & gt; The size/2 + 1;

Well? I'm into this kind of writing, because I think using displacement operation would be faster,, so just wrote, but feel no problem give me a warning, have questions, or thank you

Can also casts the first shift again,

 (unsigned int) (p - & gt; The size) & gt;> 1

CodePudding user response:

Clang - Tidy static checking more stringent, bit operation must use an unsigned number, including constant,
In pl - & gt; The size & gt;> 1, light pl - & gt; The size is unsigned weren't enough, one must also be,
So, to pl - & gt; The size & gt;> 1 u, there will be no warning,

CodePudding user response:

The size change to unsigned
P - & gt; The size & gt;> 1 u
So I can

CodePudding user response:

Dare to use clang apes, all has the qualification as a lawyer, a.