determine residency of memory pages
*addr, size_t len,
mincore() system call allows a process to obtain
information about whether pages are core resident. Here the current core
residency of the pages is returned in the character array
vec, with a value of 1 meaning that the page is in-core.
Upon successful completion, the value 0 is returned; otherwise the
value -1 is returned and the global variable
errno is set to indicate the error.
mincore() function first appeared in