what happens when you invoke malloc() on a unix system
malloc() library function internally calls brk() or sbrk() system call,which allocates memory fo data region,so local static variables and global variables will have allocation of memory from heap increasing the effective size of data region.now my question is what exactly is happening when i allocate memory to int *a?which is local variable. i might have misconception please let me know if any.thanks
int *p itself is a local variable, which is a pointer (these days: usually four or eight bytes, usually on the stack or in a register). When you do p = malloc(...) , you are allocating memory (on the heap - or what is these days conventionally called 'the heap' even if a heap is not the structure used to manage free memory) and assigning a pointer to that memory into p .
When you call malloc() you get access to the amount of memory requested, or NULL is returned. That is all that is guaranteed. Everything else is implementation dependent. The mechanism by which you get access to that memory can be quite varied.
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