Why is memory not released back to the operating system after an array is deleted?
By Eric Korpela of Berkeley This is a result of IDL being written in C and using the C library functions (malloc and free) for memory allocation. In most C libraries, memory that is freed is NOT returned to the operating system. The C program retains this memory and will reuse it for future calls to malloc (assuming that the new allocation will fit in the freed block). Another way of considering it is in terms of how memory allocation is done under UNIX. New memory is allocated using brk() or sbrk() which control the size of the data segment. These routines are called by malloc().
