Using NULL in C

Question

Possible Duplicate    Do you use NULL or 0  zero  for pointers in C          Is it a good idea to use NULL in C   or just the value 0   Is there a special circumstance using NULL in C code calling from C    Like SDL

User · Answer

I never use NULL in my C or C   code  0 works just fine  as does if  ptrname   Any competent C or C   programmer should know what those do

User · Answer

The downside of NULL in C   is that it is a define for 0  This is a value that can be silently converted to pointer  a bool value  a float double  or an int   That is not very type safe and has lead to actual bugs in an application I worked on    Consider this   void Foo int i   void Foo Bar  b   void Foo bool b     main          Foo 0                 Foo NULL      same as Foo 0       C  11 defines a nullptr that is convertible to a null pointer but not to other scalars  This is supported in all modern C   compilers  including VC   as of 2008  In older versions of GCC there is a similar feature  but then it was called   null

User · Answer

Assuming that you don t have a library or system header that defines NULL as for example  void  0 or  char  0 it s fine  I always tend to use 0 myself as it is by definition the null pointer  In c  0x you ll have nullptr available so the question won t matter as much anymore

User · Answer

In C   NULL expands to 0 or 0L  See this quote from Stroustrup s FAQ   Should I use NULL or 0  In C    the definition of NULL is 0  so there is only an aesthetic difference  I prefer to avoid macros  so I use 0  Another problem with NULL is that people sometimes mistakenly believe that it is different from 0 and or not an integer  In pre-standard code  NULL was is sometimes defined to something unsuitable and therefore had has to be avoided  That s less common these days  If you have to name the null pointer  call it nullptr  that s what it s called in C  11  Then   quot nullptr quot  will be a keyword

User · Answer

From crtdbg h  and many other headers     ifndef NULL  ifdef   cplusplus  define NULL    0  else  define NULL      void   0   endif  endif   Therefore NULL is 0  at least on the Windows platform  So no  not that I know of

[c++] Using NULL in C++?

Examples related to c++

Examples related to null