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arrayspointersfreeunsignedcalloc

how free unsigned pointer array and it's elements (calloc)

What is the best way to free unsigned pointer array allocated with cmallc?

 uint8_t *buf;
 buf = cs_calloc(ca->len + 13);

i do like this , but i know this is not quite right , since i got compile warning :

warning: passing argument 1 of ‘free’ makes pointer from integer without a cast

for (i = 0; i < ca->len + 13; i++)
{   
 free(buf[i]);
buf[i] = NULL;
}

free(buf);

here is cs_calloc code :

void *cs_calloc(size_t size){

 return (calloc (1,size));
 }

my question are 1. the way i free , buf , i mean first free each of array's element in a loop (free (buf[i]) is correct? do i need to free the elements of array , and the free the array as above

  1. why do i get that compile warning , and if it's wrong , could somebody please correct the way i free the allocated memory (please write me the code how should be corrected ?

Thanks in advance

Solution

  • You just need free(buf) and nothing more - so just drop the for and you're set. Trying to free(buf[i]) is wrong and will trick the library into treating buf[i] (a small integer) as a pointer.

    There's one and only one simple rule: only free what you received from malloc or calloc.

    why that compile warning happened

    You got the warning because you called free with an integer when free expects a pointer.