What's the point of malloc(0)?

c malloc
jldupont picture jldupont · Jan 7, 2010 · Viewed 68.7k times · Source

I just saw this code:

artist = (char *) malloc(0);

...and I was wondering why would one do this?

Answer

Reed Copsey picture Reed Copsey · Jan 7, 2010

According to the specifications, malloc(0) will return either "a null pointer or a unique pointer that can be successfully passed to free()".

This basically lets you allocate nothing, but still pass the "artist" variable to a call to free() without worry. For practical purposes, it's pretty much the same as doing:

artist = NULL;

Related questions

Difference between malloc and calloc?

What is the difference between doing: ptr = (char **) malloc (MAXELEMS * sizeof(char *)); or: ptr = (char **) calloc (MAXELEMS, sizeof(char*)); When is it a good idea to use calloc over malloc or vice versa?

Read More
Do I cast the result of malloc?

In this question, someone suggested in a comment that I should not cast the result of malloc, i.e. int *sieve = malloc(sizeof(int) * length); rather than: int *sieve = (int *) malloc(sizeof(int) * length); Why would this be the case?

Read More
Using malloc for allocation of multi-dimensional arrays with different row lengths

I have the following C code : int *a; size_t size = 2000*sizeof(int); a = (int *) malloc(size); which works fine. But if I have the following : char **b = malloc(2000*sizeof *b); where every element of b has different length. How …

Read More