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Does Standard define null pointer constant to have all bits set to zero?


Does Standard define null pointer constant to have all bits set to zero?

By : Dragos
Date : November 22 2020, 10:40 AM
may help you . No, NULL doesn't have to be all bits zero.
N1570 6.3.2.3 Pointers paragraph 3:
code :


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The null-pointer-constant is not specified using the NULL macro

The null-pointer-constant is not specified using the NULL macro


By : Arto Ojala
Date : March 29 2020, 07:55 AM
I think the issue was by ths following , The value for the NULL macro is implementation defined in C++.
With that in mind, it's reasonable that your static analysis tool is complaining about you using a value defined by yourself which may be wrong. ( even if it will work with basically all compilers )
code :
int foo( int   );
int foo( int * );

foo( NULL    ); // Will call first overload if NULL is defined as 0
foo( nullptr ); // Will call second overload as nullptr is not implicitly convertable to non-pointer types.
How to define global constant char pointer in C and redefine poiting value throughout files

How to define global constant char pointer in C and redefine poiting value throughout files


By : Power Chord
Date : March 29 2020, 07:55 AM
I hope this helps you . i'm quite new in C, what i'm trying to do is define a pointer with a constant address, this is my attempt in testHeader.h: , There's two problems with that line:
code :
char * const MY_VAR_P = ...;
C - How is the Null Pointer a constant?

C - How is the Null Pointer a constant?


By : devbg01
Date : March 29 2020, 07:55 AM
hope this fix your issue A constant is defined as fixed values that cannot be altered by the program. E.g. Direct values like 1, 2, 3, 'a' and also defined constants like #define CONSTANT 100 , For the same reason this works:
code :
int x = 1;
x = 2;
How to write C/C++ code correctly when null pointer is not all bits zero

How to write C/C++ code correctly when null pointer is not all bits zero


By : Jamal Shaikh
Date : March 29 2020, 07:55 AM
To fix this issue As the comp.lang.c FAQ says, there are architectures where the null pointer is not all bits zero. So the question is what actually checks the following construction: , According to the C spec:
What is the difference between a null pointer constant (nullptr), a null pointer value and a null member pointer value?

What is the difference between a null pointer constant (nullptr), a null pointer value and a null member pointer value?


By : user3637968
Date : March 29 2020, 07:55 AM
Any of those help
What is the difference between a null pointer constant (nullptr), a null pointer value and a null member pointer value?
code :
NULL  // a macro for one of the others
0
0L
nullptr

std::nullptr_t fun();
fun() // also a null pointer constant
(void*)nullptr     // pointer to void
(int*)nullptr      // pointer to object

using void_fun = void();
(void_fun*)nullptr // pointer to function
(int some_class::*)nullptr // pointer to data member

using mem_void_fun_ptr = void(some_class::*)(); // unfortunately cannot alias member
                                                // function type as far as I know,
                                                // so we alias pointer to it instead
(mem_void_fun_ptr)nullptr  // pointer to member function
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