diff options
| author | Alejandro Colomar <alx@kernel.org> | 2023-03-17 17:08:01 +0100 |
|---|---|---|
| committer | Alejandro Colomar <alx@kernel.org> | 2023-03-30 15:14:55 +0200 |
| commit | 4131356cdab8d37fc395ca5466a0401c8573380c (patch) | |
| tree | 8c4c6f1c3172358b735b481cbbfdd9cc04b00ed9 /man2/mmap.2 | |
| parent | fd00f831b52d61a91d59cb3b46182869145d9700 (diff) | |
| download | man-pages-4131356cdab8.tar.gz | |
man*/, man-pages.7: VERSIONS, STANDARDS, HISTORY: Reorganize sections
- Add a new HISTORY section that covers the history of an API, both
regarding implementations and regarding old standards. This was
previously covered in VERSIONS, and in some cases in STANDARDS.
- Repurpose VERSIONS to cover differing implementations in _current_
systems.
- STANDARDS is reduced to only cover current versions of standards.
That basically means only C11 (C99 has been superseeded by C11; C17
is just a bugfix of C11, so not really a new version), and
POSIX.1-2008 (*-2001 was superseeded by *-2008; *-2017 was just a
bugfix for *-2008). The section also mentions for example 'Linux',
'GNU' or 'BSD' when a non-standard API is Linux- or GNU-only or if
it's (de-facto) standard in the BSDs.
- In some cases content that should go into one of these sections was
in NOTES. Move it from there to where it corresponds.
- In the SYNOPSIS, I added [[deprecated]] in some functions that I
found are deprecated by the relevant standards.
- A few other related changes...
Cc: Oskari Pirhonen <xxc3ncoredxx@gmail.com>
Signed-off-by: Alejandro Colomar <alx@kernel.org>
Diffstat (limited to 'man2/mmap.2')
| -rw-r--r-- | man2/mmap.2 | 102 |
1 files changed, 52 insertions, 50 deletions
diff --git a/man2/mmap.2 b/man2/mmap.2 index 6a9395d2c2..04f117e02d 100644 --- a/man2/mmap.2 +++ b/man2/mmap.2 @@ -665,41 +665,7 @@ T} Thread safety MT-Safe .hy .ad .sp 1 -.SH STANDARDS -POSIX.1-2001, POSIX.1-2008, SVr4, 4.4BSD. -.\" SVr4 documents additional error codes ENXIO and ENODEV. -.\" SUSv2 documents additional error codes EMFILE and EOVERFLOW. -.PP -On POSIX systems on which -.BR mmap (), -.BR msync (2), -and -.BR munmap () -are available, -.B _POSIX_MAPPED_FILES -is defined in \fI<unistd.h>\fP to a value greater than 0. -(See also -.BR sysconf (3).) -.\" POSIX.1-2001: It shall be defined to -1 or 0 or 200112L. -.\" -1: unavailable, 0: ask using sysconf(). -.\" glibc defines it to 1. -.SH NOTES -Memory mapped by -.BR mmap () -is preserved across -.BR fork (2), -with the same attributes. -.PP -A file is mapped in multiples of the page size. -For a file that is not -a multiple of the page size, -the remaining bytes in the partial page at the end of the mapping -are zeroed when mapped, -and modifications to that region are not written out to the file. -The effect of -changing the size of the underlying file of a mapping on the pages that -correspond to added or removed regions of the file is unspecified. -.PP +.SH VERSIONS On some hardware architectures (e.g., i386), .B PROT_WRITE implies @@ -760,6 +726,57 @@ The relevant flags are: .BR MAP_POPULATE , and .BR MAP_STACK . +.SS C library/kernel differences +This page describes the interface provided by the glibc +.BR mmap () +wrapper function. +Originally, this function invoked a system call of the same name. +Since Linux 2.4, that system call has been superseded by +.BR mmap2 (2), +and nowadays +.\" Since around glibc 2.1/2.2, depending on the platform. +the glibc +.BR mmap () +wrapper function invokes +.BR mmap2 (2) +with a suitably adjusted value for +.IR offset . +.SH STANDARDS +POSIX.1-2008. +.SH HISTORY +POSIX.1-2001, SVr4, 4.4BSD. +.\" SVr4 documents additional error codes ENXIO and ENODEV. +.\" SUSv2 documents additional error codes EMFILE and EOVERFLOW. +.PP +On POSIX systems on which +.BR mmap (), +.BR msync (2), +and +.BR munmap () +are available, +.B _POSIX_MAPPED_FILES +is defined in \fI<unistd.h>\fP to a value greater than 0. +(See also +.BR sysconf (3).) +.\" POSIX.1-2001: It shall be defined to -1 or 0 or 200112L. +.\" -1: unavailable, 0: ask using sysconf(). +.\" glibc defines it to 1. +.SH NOTES +Memory mapped by +.BR mmap () +is preserved across +.BR fork (2), +with the same attributes. +.PP +A file is mapped in multiples of the page size. +For a file that is not +a multiple of the page size, +the remaining bytes in the partial page at the end of the mapping +are zeroed when mapped, +and modifications to that region are not written out to the file. +The effect of +changing the size of the underlying file of a mapping on the pages that +correspond to added or removed regions of the file is unspecified. .PP An application can determine which pages of a mapping are currently resident in the buffer/page cache using @@ -860,21 +877,6 @@ and .I length must both be a multiple of the underlying huge page size. .\" -.SS C library/kernel differences -This page describes the interface provided by the glibc -.BR mmap () -wrapper function. -Originally, this function invoked a system call of the same name. -Since Linux 2.4, that system call has been superseded by -.BR mmap2 (2), -and nowadays -.\" Since around glibc 2.1/2.2, depending on the platform. -the glibc -.BR mmap () -wrapper function invokes -.BR mmap2 (2) -with a suitably adjusted value for -.IR offset . .SH BUGS On Linux, there are no guarantees like those suggested above under .BR MAP_NORESERVE . |