macro and variable have the same name

[ettlmartin]

consider the code below

#include <iostream>

int main()
{
	int foo=1;
	#define foo (4 + foo)
	std::cout << "foo: " <<foo << std::endl;
}

the macro definition and the integer variable have the same name. This can result in unpredicted results.

running the testprogramm prints

foo:5

Best regards

Martin

[hyd_danmar]

Can you clarify the problem?

cppcheck will tokenize and simplify the code into:

##file 0
1: int main ( )
2: {
3: int foo@1 ; foo@1 = 1 ;
4:
5: std :: cout << "foo: " << ( 4 + foo@1 ) << std :: endl ;
6: }

And to me that looks correct. I would prefer though if the "foo@1" on line 5 were simplified to "1".

[aggro80]

to hyd_danmar: This is a new check request. It was asked that we check if variable and macro have the same name and print error (style?) about it.

E.g. something like:

[file.cpp:6] (style) Macro and variable foo share the same name. Consider renaming either one to avoid confusion.

I think this could be a valid for style error.

[ettlmartin]

Replying to hyd_danmar:

Can you clarify the problem?

cppcheck will tokenize and simplify the code into:

##file 0
1: int main ( )
2: {
3: int foo@1 ; foo@1 = 1 ;
4:
5: std :: cout << "foo: " << ( 4 + foo@1 ) << std :: endl ;
6: }

And to me that looks correct. I would prefer though if the "foo@1" on line 5 were simplified to "1".

The issue in the code above is that a macro definition has the same name as a variable. I see, its correctly tokenized by cppcheck. Nevertheless, this can lead (in larger projects) to unpredicted output/behaviour. Because these are issues, that hard to find. Imagine you have thousends lines of code.... so it would be really helpful if cppcheck could warn about that. Maybe as a style error?

Best regards

Martin

[hyd_danmar]

Ok, I understand. I agree, it would be a good check to have.
Thank you

[hyd_danmar]

IMHO this is a bit out of scope. Because it can't be checked in the token lists.