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| 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/nanosleep.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/nanosleep.2')
| -rw-r--r-- | man2/nanosleep.2 | 46 |
1 files changed, 24 insertions, 22 deletions
diff --git a/man2/nanosleep.2 b/man2/nanosleep.2 index 12e0cee84b..1224192961 100644 --- a/man2/nanosleep.2 +++ b/man2/nanosleep.2 @@ -109,27 +109,7 @@ The value in the field was not in the range [0, 999999999] or .I tv_sec was negative. -.SH STANDARDS -POSIX.1-2001, POSIX.1-2008. -.SH NOTES -If the interval specified in -.I req -is not an exact multiple of the granularity underlying clock (see -.BR time (7)), -then the interval will be rounded up to the next multiple. -Furthermore, after the sleep completes, there may still be a delay before -the CPU becomes free to once again execute the calling thread. -.PP -The fact that -.BR nanosleep () -sleeps for a relative interval can be problematic if the call -is repeatedly restarted after being interrupted by signals, -since the time between the interruptions and restarts of the call -will lead to drift in the time when the sleep finally completes. -This problem can be avoided by using -.BR clock_nanosleep (2) -with an absolute time value. -.PP +.SH VERSIONS POSIX.1 specifies that .BR nanosleep () should measure time against the @@ -161,7 +141,11 @@ function; ... Consequently, these time services shall expire when the requested relative interval elapses, independently of the new or old value of the clock. .RE -.SS Old behavior +.SH STANDARDS +POSIX.1-2008. +.SH HISTORY +POSIX.1-2001. +.PP In order to support applications requiring much more precise pauses (e.g., in order to control some time-critical hardware), .BR nanosleep () @@ -173,6 +157,24 @@ or .BR SCHED_RR . This special extension was removed in Linux 2.5.39, and is thus not available in Linux 2.6.0 and later kernels. +.SH NOTES +If the interval specified in +.I req +is not an exact multiple of the granularity underlying clock (see +.BR time (7)), +then the interval will be rounded up to the next multiple. +Furthermore, after the sleep completes, there may still be a delay before +the CPU becomes free to once again execute the calling thread. +.PP +The fact that +.BR nanosleep () +sleeps for a relative interval can be problematic if the call +is repeatedly restarted after being interrupted by signals, +since the time between the interruptions and restarts of the call +will lead to drift in the time when the sleep finally completes. +This problem can be avoided by using +.BR clock_nanosleep (2) +with an absolute time value. .SH BUGS If a program that catches signals and uses .BR nanosleep () |