Static array of structs with pointers

Question

We have an array of structs like this one:

struct allocation
{
  size_t alloc_size_;

  char* alloc_memory_;
};

static struct allocation allocations[] =
  {{1024, NULL},{2048, NULL},};

later on in main() it's members alloc_memory_ are initialized using numa_alloc_onnode().

So the question: is alloc_memory_ also static and where they are located (heap, stack) ? If they are not static then how to make them static?

fluter · Accepted Answer · 2016-04-19 22:55:12Z

2

The alloc_memory_ member of array allocations are static, but the memory the pointed to are not necessarily static.

In your case, since you allocated them with numa_alloc_onnode in main, this means they pointed to dynamic storage.

If you really want static storage too, you can define the memory before the structure:

static char buffer1[1024];
static char buffer2[2048];

static struct allocation allocations[] = 
{ {1024, buffer1}, {2048, buffer2} };

answered Apr 19, 2016 at 22:55

fluter

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2 Comments

Dimon Over a year ago

Ok thanks. In this case I would need a macro that would generate code type static char bufferN[SIZE];. Consider that static struct allocation allocations[] above is initialized as static struct allocation allocations[] = ALLOCATIONS;, where ALLOCATIONS is defined at compile time by user like -D'ALLOCATIONS={ {1024, buffer1}, {2048, buffer2} }' So the macro would have to parse { {1024, buffer1}, {2048, buffer2} } and generate code: static char buffer1[1024]; static char buffer2[2048];. Could you please point me to such a macro? Thanks

fluter Over a year ago

I suggest not passing code through macros, you could pass the size of the buffer though, static char buffer[N}; and -DN=1024

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