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mmap2

NAME

mmap2 - map files or devices into memory

SYNOPSIS

#include <sys/mman.h>


#include <syscall.h>


#include <errno.h>
_syscall6(void *, mmap2, void *, start, size_t, length,
          int, prot, int, flags, int, fd, off_t, pgoffset)
          /* Using syscall(2) may be preferable; see intro(2) */
void * mmap2(void *start, size_t length, int prot,
             int flags, int fd, off_t pgoffset);

DESCRIPTION

The mmap2() system call operates in exactly the same way as mmap(2), except that the final argument specifies the offset into the file in 4kB units (instead of bytes). This enables applications that use a 32-bit off_t to map larger files (typically up to 2^44 bytes).

RETURN VALUE

On success, mmap2() returns a pointer to the mapped area. On error -1 is returned and errno is set appropriately.

ERRORS

EFAULT

Problem with getting the data from userspace.

NOTES

mmap2() is available since Linux 2.3.31. It is Linux specific, and should be avoided in portable applications. On 32-bit systems, mmap2() is used to implement the mmap64() function that is part of the LFS (Large File Summit).

CONFORMING TO

This system call is Linux specific.

SEE ALSO

getpagesize(2), mmap(2), mremap(2), msync(2), shm_open(3)