man2/mmap2.2

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  25 .\" Modified 31 Jan 2002, Michael Kerrisk <mtk-manpages@gmx.net>
  26 .\"     Added description of mmap2
  27 .\" Modified, 2004-11-25, mtk -- removed stray #endif in prototype
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  29 .TH MMAP2 2 2002-01-31 "Linux 2.3.31" "Linux Programmer's Manual"
  30 .SH NAME
  31 mmap2 \- map files or devices into memory
  32 .SH SYNOPSIS
  33 .nf
  34 .B #include <sys/mman.h>
  35 .br
  36 .B #include <syscall.h>
  37 .br
  38 .B #include <errno.h>
  39 .sp
  40 .BI "_syscall6(void *, " mmap2 ", void *, " start ", size_t, " length ,
  41 .BI "          int, " prot ", int, " flags ", int, " fd ", off_t, " pgoffset )
  42           /* Using \fBsyscall\fP(2) may be preferable; see \fBintro\fP(2) */
  43 .sp
  44 .BI "void *mmap2(void *" start ", size_t " length ", int " prot ,
  45 .BI "             int " flags ", int " fd ", off_t " pgoffset );
  46 .fi
  47 .SH DESCRIPTION
  48 The
  49 .BR mmap2 ()
  50 system call operates in exactly the same way as
  51 .BR mmap (2),
  52 except that the final argument specifies the offset into the
  53 file in units of the system page size (instead of bytes).
  54 This enables applications that use a 32-bit
  55 .I off_t
  56 to map
  57 larger files (typically up to 2^44 bytes).
  58 .SH "RETURN VALUE"
  59 On success,
  60 .BR mmap2 ()
  61 returns a pointer to the mapped area.
  62 On error \-1 is returned
  63 and
  64 .I errno
  65 is set appropriately.
  66 .SH ERRORS
  67 .TP
  68 EFAULT
  69 Problem with getting the
  70 data from userspace.
  71 .SH NOTES
  72 .BR mmap2 ()
  73 is available since Linux 2.3.31.
  74 It is Linux specific, and should be avoided in portable applications.
  75 On 32-bit systems,
  76 .BR mmap2 ()
  77 is used to implement the
  78 .BR mmap64 ()
  79 function that is part of the LFS (Large File Summit).
  80 .SH "CONFORMING TO"
  81 This system call is Linux specific.
  82 .SH "SEE ALSO"
  83 .BR getpagesize (2),
  84 .BR mmap (2),
  85 .BR mremap (2),
  86 .BR msync (2),
  87 .BR shm_open (3)