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NAME | LIBRARY | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | STANDARDS | HISTORY | BUGS | SEE ALSO | COLOPHON |
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mincore(2) System Calls Manual mincore(2)
mincore - determine whether pages are resident in memory
Standard C library (libc, -lc)
#include <sys/mman.h>
int mincore(size_t length;
void addr[length], size_t length, unsigned char *vec);
Feature Test Macro Requirements for glibc (see
feature_test_macros(7)):
mincore():
Since glibc 2.19:
_DEFAULT_SOURCE
glibc 2.19 and earlier:
_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 to indicate the error.
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.
None.
Linux 2.3.99pre1, glibc 2.2.
First appeared in 4.4BSD.
NetBSD, FreeBSD, OpenBSD, Solaris 8, AIX 5.1, SunOS 4.1.
Before Linux 2.6.21, mincore() did not return correct information
for MAP_PRIVATE mappings, or for nonlinear mappings (established
using remap_file_pages(2)).
fincore(1), madvise(2), mlock(2), mmap(2), posix_fadvise(2),
posix_madvise(3)
This page is part of the man-pages (Linux kernel and C library
user-space interface documentation) project. Information about
the project can be found at
⟨https://www.kernel.org/doc/man-pages/⟩. If you have a bug report
for this manual page, see
⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩.
This page was obtained from the tarball man-pages-6.15.tar.gz
fetched from
⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on
2025-08-11. If you discover any rendering problems in this HTML
version of the page, or you believe there is a better or more up-
to-date source for the page, or you have corrections or
improvements to the information in this COLOPHON (which is not
part of the original manual page), send a mail to
man-pages@man7.org
Linux man-pages 6.15 2025-06-28 mincore(2)
Pages that refer to this page: fincore(1), madvise(2), mlock(2), mmap(2), posix_fadvise(2), syscalls(2)
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HTML rendering created 2025-09-06 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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