redhat man page for mincore

Query: mincore

OS: redhat

Section: 2

Format: Original Unix Latex Style Formatted with HTML and a Horizontal Scroll Bar

MINCORE(2)						     Linux Programmer's Manual							MINCORE(2)

NAME
mincore - get information on whether pages are in core
SYNOPSIS
#include <unistd.h> #include <sys/mman.h> int mincore(void *start, size_t length, unsigned char *vec);
DESCRIPTION
The mincore function requests a vector describing which pages of a file are in core and can be read without disk access. The kernel will supply data for length bytes following the start address. On return, the kernel will have filled vec with bytes, of which the least signif- icant bit indicates if a page is core resident. For mincore to return successfully, start must lie on a page boundary. It is the caller's responsibility to round up to the nearest page. The length parameter need not be a multiple of the page size. The vector vec must be large enough to contain length/PAGE_SIZE bytes. One may obtain the page size from getpagesize(2).
RETURN VALUE
On success, mincore returns zero. On error, -1 is returned, and errno is set appropriately.
ERRORS
EAGAIN kernel is temporarily out of resources EINVAL start is not a multiple of the page size, or len has a non-positive value EFAULT vec points to an invalid address ENOMEM address to address + length contained unmapped memory, or memory not part of a file.
BUGS
mincore should return a bit vector and not a byte vector. As of Linux 2.4.5, it is not possible to gain information on the core residency of pages which are not backed by a file. In other words, calling mincore on an region returned by an anonymous mmap(2) does not work and sets errno to ENOMEM. Unless pages are locked in memory, the contents of vec may be stale by the time they reach userspace.
CONFORMING TO
mincore does not appear to be part of POSIX or the Single Unix Specification.
HISTORY
The mincore() function first appeared in 4.4BSD.
AVAILABILITY
Since Linux 2.3.99pre1 and glibc 2.2.
SEE ALSO
getpagesize(2), mmap(2) Linux 2.4.5 2001-06-03 MINCORE(2)
Related Man Pages
mincore(2) - minix
mincore(2) - php
mincore(2) - posix
mincore(2) - plan9
mincore(2) - v7
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