File: autoconf.info,  Node: Null Pointers,  Next: Buffer Overruns,  Prev: Preprocessor Arithmetic,  Up: Portable C and C++++

13.4 Properties of Null Pointers
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Most modern hosts reliably fail when you attempt to dereference a null
pointer.

   On almost all modern hosts, null pointers use an all-bits-zero
internal representation, so you can reliably use ‘memset’ with 0 to set
all the pointers in an array to null values.

   If ‘p’ is a null pointer to an object type, the C expression ‘p + 0’
always evaluates to ‘p’ on modern hosts, even though the standard says
that it has undefined behavior.