mincore - determine whether pages are resident in memory
int mincore(void *addr, size_t length, unsigned
Feature Test Macro Requirements for glibc (see feature_test_macros
Since glibc 2.19:
Glibc 2.19 and earlier:
_BSD_SOURCE || _SVID_SOURCE
() returns a vector that indicates whether pages of the calling
process's virtual memory are resident in core (RAM), and so will not cause a
disk access (page fault) if referenced. The kernel returns residency
information about the pages starting at the address addr
continuing for length
argument must be a multiple of the system page size. The
argument need not be a multiple of the page size, but since
residency information is returned for whole pages, length
effectively rounded up to the next multiple of the page size. One may obtain
the page size (PAGE_SIZE
) using sysconf(_SC_PAGESIZE)
argument must point to an array containing at least
(length+PAGE_SIZE-1) / PAGE_SIZE
bytes. On return, the least
significant bit of each byte will be set if the corresponding page is
currently resident in memory, and be clear otherwise. (The settings of the
other bits in each byte are undefined; these bits are reserved for possible
later use.) Of course the information returned in vec
is only a
snapshot: pages that are not locked in memory can come and go at any moment,
and the contents of vec
may already be stale by the time this call
On success, mincore
() returns zero. On error, -1 is returned, and
is set appropriately.
kernel is temporarily out of resources.
- vec points to an invalid address.
- addr is not a multiple of the page size.
- length is greater than (TASK_SIZE - addr). (This
could occur if a negative value is specified for length, since that
value will be interpreted as a large unsigned integer.) In Linux 2.6.11
and earlier, the error EINVAL was returned for this condition.
- addr to addr + length contained unmapped memory.
Available since Linux 2.3.99pre1 and glibc 2.2.
() is not specified in POSIX.1, and it is not available on all
Before kernel 2.6.21, mincore
() did not return correct information for
mappings, or for nonlinear mappings (established using