[wireties]

In your example input1 DOES take up space in memory (whether or not you call the calloc), 4 bytes on the stack of the vxWorks task in which it executes. After the calloc call, input1 contains an address that points to a location in the heap. The space used in the heap is probably 4 bytes but could be more. For example vxWorks has an option to insert boundaries around heap allocations (where it inserts a certain pattern) to assist in memory analysis. Greg's observations about alignment also play a role.

The data type referred to by the pointer does NOT changed the amount of memory the pointer itself consumes. But it does determine how pointer arithmetic increments/decrements. For your example, input1++ increases the address pointed to by 4 bytes. If input1 were declared to pointer to a double, it would increase by 8 bytes and so on.

I think our version of the PowerPC is a 32-bit machine thus integers and pointers are 4-bytes.

HTH