MINCORE(2) manual page
Table of Contents
mincore - determine whether pages are
resident in memory
#include <unistd.h>
#include <sys/mman.h>
int mincore(void *addr, size_t length, unsigned char
*vec);
Feature Test Macro Requirements for glibc (see feature_test_macros(7)
):
mincore(): _BSD_SOURCE || _SVID_SOURCE
mincore() 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, and continuing for length bytes.
The addr
argument must be a multiple of the system page size. The length argument
need not be a multiple of the page size, but since residency information
is returned for whole pages, length is effectively rounded up to the next
multiple of the page size. One may obtain the page size (PAGE_SIZE) using
sysconf(_SC_PAGESIZE).
The vec 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 returns.
On success,
mincore() returns zero. On error, -1 is returned, and errno is set appropriately.
EAGAIN kernel is temporarily out of resources.
- EFAULT
- vec points to
an invalid address.
- EINVAL
- addr is not a multiple of the page size.
- ENOMEM
- 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.
- ENOMEM
- addr to addr + length contained unmapped
memory.
Available since Linux 2.3.99pre1 and glibc 2.2.
mincore()
is not specified in POSIX.1-2001, and it is not available on all UNIX implementations.
Before kernel 2.6.21, mincore() did not return correct information
for MAP_PRIVATE mappings, or for nonlinear mappings (established using
remap_file_pages(2)
).
mlock(2)
, mmap(2)
This
page is part of release 3.78 of the Linux man-pages project. A description
of the project, information about reporting bugs, and the latest version
of this page, can be found at http://www.kernel.org/doc/man-pages/.
Table of Contents
![[Go to CFHT Home Page]](/images/cfht-icon.gif){kind=icon}
Man Pages 
Back to Software Index 
Manpage Top Level