prctl.2: ffix

[thirdparty/man-pages.git] / man2 / mmap2.2

diff --git a/man2/mmap2.2 b/man2/mmap2.2
index c28efbb29ba05920e03edcd4c767a90be86f85ee..c571cc3021c61be1e159b2b5676178d6fcb58a90 100644 (file)
--- a/man2/mmap2.2
+++ b/man2/mmap2.2
@@ -1,7 +1,6 @@
-.\" Hey Emacs! This file is -*- nroff -*- source.
-.\"
 .\" Copyright (C) 2002, Michael Kerrisk
 .\"
+.\" %%%LICENSE_START(VERBATIM)
 .\" Permission is granted to make and distribute verbatim copies of this
 .\" manual provided the copyright notice and this permission notice are
 .\" preserved on all copies.
@@ -21,65 +20,79 @@
 .\"
 .\" Formatted or processed versions of this manual, if unaccompanied by
 .\" the source, must acknowledge the copyright and authors of this work.
+.\" %%%LICENSE_END
 .\"
-.\" Modified 31 Jan 2002, Michael Kerrisk <mtk-manpages@gmx.net>
+.\" Modified 31 Jan 2002, Michael Kerrisk <mtk.manpages@gmail.com>
 .\"    Added description of mmap2
 .\" Modified, 2004-11-25, mtk -- removed stray #endif in prototype
 .\"
-.TH MMAP2 2 2002-01-31 "Linux 2.3.31" "Linux Programmer's Manual"
+.TH MMAP2 2 2017-09-15 "Linux" "Linux Programmer's Manual"
 .SH NAME
 mmap2 \- map files or devices into memory
 .SH SYNOPSIS
 .nf
 .B #include <sys/mman.h>
-.br
-.B #include <syscall.h>
-.br
-.B #include <errno.h>
-.sp
-.BI "_syscall6(void *, " mmap2 ", void *, " start ", size_t, " length ,
-.BI "          int, " prot ", int, " flags ", int, " fd ", off_t, " pgoffset )
-          /* Using \fBsyscall\fP(2) may be preferable; see \fBintro\fP(2) */
-.sp
-.BI "void *mmap2(void *" start ", size_t " length ", int " prot ,
+.PP
+.BI "void *mmap2(void *" addr ", size_t " length ", int " prot ,
 .BI "             int " flags ", int " fd ", off_t " pgoffset );
 .fi
 .SH DESCRIPTION
+This is probably not the system call that you are interested in; instead, see
+.BR mmap (2),
+which describes the glibc wrapper function that invokes this system call.
+.PP
 The
 .BR mmap2 ()
-system call operates in exactly the same way as
+system call provides the same interface as
 .BR mmap (2),
 except that the final argument specifies the offset into the
-file in units of the system page size (instead of bytes).
+file in 4096-byte units (instead of bytes, as is done by
+.BR mmap (2)).
 This enables applications that use a 32-bit
 .I off_t
-to map
-larger files (typically up to 2^44 bytes).
-.SH "RETURN VALUE"
+to map large files (up to 2^44 bytes).
+.SH RETURN VALUE
 On success,
 .BR mmap2 ()
 returns a pointer to the mapped area.
-On error \-1 is returned
-and
+On error, \-1 is returned and
 .I errno
 is set appropriately.
 .SH ERRORS
 .TP
 .B EFAULT
-Problem with getting the
-data from userspace.
-.SH NOTES
+Problem with getting the data from user space.
+.TP
+.B EINVAL
+(Various platforms where the page size is not 4096 bytes.)
+.I "offset\ *\ 4096"
+is not a multiple of the system page size.
+.PP
 .BR mmap2 ()
-is available since Linux 2.3.31.
-It is Linux specific, and should be avoided in portable applications.
-On 32-bit systems,
+can also return any of the errors described in
+.BR mmap (2).
+.SH VERSIONS
 .BR mmap2 ()
-is used to implement the
-.BR mmap64 ()
-function that is part of the LFS (Large File Summit).
-.SH "CONFORMING TO"
-This system call is Linux specific.
-.SH "SEE ALSO"
+is available since Linux 2.3.31.
+.SH CONFORMING TO
+This system call is Linux-specific.
+.SH NOTES
+On architectures where this system call is present,
+the glibc
+.BR mmap ()
+wrapper function invokes this system call rather than the
+.BR mmap (2)
+system call.
+.PP
+This system call does not exist on x86-64.
+.PP
+On ia64, the unit for
+.I offset
+is actually the system page size, rather than 4096 bytes.
+.\" ia64 can have page sizes ranging from 4 kB to 64 kB.
+.\" On cris, it looks like the unit might also be the page size,
+.\" which is 8192 bytes. -- mtk, June 2007
+.SH SEE ALSO
 .BR getpagesize (2),
 .BR mmap (2),
 .BR mremap (2),