when to use below type of macro ?

Qt embedded developer

I want to know when to use below type of macro ? i want to understand this macro also.

what is application of it ?

#define NULL_PTR ((void *) 0L)

Chris Kawa

@Qt-embedded-developer said:

I want to know when to use below type of macro ?

Almost never. It's obsolete. Maybe if you're writing some retro-code for an ancient compiler as a hobby, but that's it. Not in any modern code.

i want to understand this macro also.

It creates a pointer to void with a value of 0. C++11 introduced nullptr to do the same without hacking the type system.

what is application of it ?

Currently none. It's obsolete. It was used to have a pointer type with a value of 0. Now you have nullptr.

Christian Ehrlicher

This is no longer needed since all compilers supported by Qt support c++11 and therefore the 'nullptr' keyword. I'm pretty sure it's no longer available in Qt6.

Qt embedded developer

@Christian-Ehrlicher dear this doesn't matter can you tell me what i mentioned in post?

Chris Kawa

@Qt-embedded-developer said:

I want to know when to use below type of macro ?

Almost never. It's obsolete. Maybe if you're writing some retro-code for an ancient compiler as a hobby, but that's it. Not in any modern code.

i want to understand this macro also.

It creates a pointer to void with a value of 0. C++11 introduced nullptr to do the same without hacking the type system.

what is application of it ?

Currently none. It's obsolete. It was used to have a pointer type with a value of 0. Now you have nullptr.

mpergand

@Qt-embedded-developer said in when to use below type of macro ?:

#define NULL_PTR ((void *) 0L)

In C, the macro NULL may have the type void*, but that is not allowed in C++.

see: https://en.cppreference.com/w/cpp/types/NULL