How to initialize static pointer with malloc in C?

c static malloc constants initializer
Arash Fotouhi picture Arash Fotouhi · May 24, 2013 · Viewed 16.3k times · Source

I'm trying to initiate a static variable (inside a function) with malloc in C, but I'm getting the "initializer not constant error". I know that I can't initiate a static with non constants in C, but can anyone think of a solution? I need the code to have the same effect as this:

static int *p = (int *)malloc(sizeof(int));

Is there a trick/workaround?

EDIT: I have a function that is called every time a flag goes high. In this function, I'm creating and starting a new thread. I declare a pointer to a struct and use malloc to allocate memory then pass this pointer to the thread. Then the function returns control. When I re-enter the function, the thread that I opened initially will still be running and I want to be able to access the memory region that I originally passed to the thread. That's why I need a static so that I can malloc on the first call and then use the same address on subsequent calls. This way I can get info from the thread. All this to avoid using global variables.

Answer

BLUEPIXY picture BLUEPIXY · May 24, 2013 
static int *p = NULL;
if(!p) p = (int *)malloc(sizeof(int));

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