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mincore(2) [freebsd man page]

MINCORE(2)						      BSD System Calls Manual							MINCORE(2)

NAME
mincore -- determine residency of memory pages LIBRARY
Standard C Library (libc, -lc) SYNOPSIS
#include <sys/mman.h> int mincore(const void *addr, size_t len, char *vec); DESCRIPTION
The mincore() system call determines whether each of the pages in the region beginning at addr and continuing for len bytes is resident. The status is returned in the vec array, one character per page. Each character is either 0 if the page is not resident, or a combination of the following flags (defined in <sys/mman.h>): MINCORE_INCORE Page is in core (resident). MINCORE_REFERENCED Page has been referenced by us. MINCORE_MODIFIED Page has been modified by us. MINCORE_REFERENCED_OTHER Page has been referenced. MINCORE_MODIFIED_OTHER Page has been modified. MINCORE_SUPER Page is part of a "super" page. (only i386 & amd64) The information returned by mincore() may be out of date by the time the system call returns. The only way to ensure that a page is resident is to lock it into memory with the mlock(2) system call. RETURN VALUES
The mincore() function returns the value 0 if successful; otherwise the value -1 is returned and the global variable errno is set to indicate the error. ERRORS
The mincore() system call will fail if: [ENOMEM] The virtual address range specified by the addr and len arguments is not fully mapped. [EFAULT] The vec argument points to an illegal address. SEE ALSO
madvise(2), mlock(2), mprotect(2), msync(2), munmap(2), getpagesize(3) HISTORY
The mincore() system call first appeared in 4.4BSD. BSD
January 17, 2003 BSD

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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)
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