What is the meaning of NULL != value in C++? [duplicate]

Question

Possible Duplicate:
What is the difference between these (bCondition == NULL) and (NULL==bCondition)?

I was going through a piece of C++ code and came across a code like

if (NULL != threadInfo)
{
  ...
  ...
}

I was just wondering is there any difference between using the expression

if (threadInfo != NULL)
{
  ...
  ...
}

what is said above. While reading the first one reads " If NULL not equals to ThreadInfo" and the second one reads "If threadInfo not equals to NULL". To me the second one makes more sense.

Answer 1

It's for safety, so you don't accidentally write

threadInfo = NULL

instead of

threadInfo == NULL

For the != there's no need to do this, but it's consistent.

Answer 2

No, there is no difference. In case of == there might be some difference. The thing is that if you accidentally write = instead of == the compiler will give an error in the first case.

if (threadInfo = NULL) //always false. The compiler will give you a warning at best

if (NULL = threadInfo) //Compiler error

I personally hate that practice and think it's better to write code that can be read in a normal human language, not Yoda language.