emo/procps
1
0
Fork 0
Code Issues Pull Requests Packages Releases Activity

docs: Merge procps_linux_version into misc

Browse Source
This commit is contained in:
Craig Small
2020-12-21 12:32:57 +11:00
parent 86957343b0
commit 7246249b8c
2 changed files with 59 additions and 93 deletions
Download Patch File Download Diff File Expand all files Collapse all files

59
doc/procps_misc.3
View File

@ -29,9 +29,17 @@ procps_misc \- API to system information in the /proc filesystem
.B long procps_hertz_get(void);
.BI "int procps_loadavg(double * " av1 ", double * " av5 ", double * " av15 ");"
.B unsigned int procps_pid_length(void);
.PP
.B #include <proc/version.h>
.PP
.B int procps_linux_version(void);
.sp
Link with \fI\-lprocps\fP.
.SH DESCRIPTION
This manual page describes the miscellaneous API functions of the
.B procps
library.
.BR procps_cpu_count ()
returns the number of CPUs that are currently online. On most systems returns
the value of
@ -56,6 +64,31 @@ Returns the maximum string length for a PID on the system. For example, if the l
possible PID value on was 123, then the length would be 3. If the file
\fI/proc/sys/kernel/pid_max\fR is unreadable, the value is assumed to be \fI5\fR.
.BR procps_linux_version ()
returns the current Linux version as an integer. On non-Linux systems that
have an emulated proc filesystem this function returns the version of the
Linux emulation instead.
The Linux version consists of a triple of positive integers representing
the major, minor and patch versions of the kernel.
.PP
The library provides 3 macros for separating out the components.
.RS 4
.TP 1.2i
.BR LINUX_VERSION_MAJOR (ver)
Extract the major component from the given version integer.
.TP
.BR LINUX_VERSION_MINOR (ver)
Extract the minor component from the given version integer.
.TP
.BR LINUX_VERSION_PATCH (ver)
Extract the patch component from the given version integer.
.RE
.PP
To encode a given Linux version, such as using it to compare against the current
version, use the following macro:
.TP
.BI LINUX_VERSION( major , minor , patch )
.SH RETURN VALUE
For
.BR procps_cpu_count "() , " procps_hertz_get "() and " procps_pid_length ()
@ -69,14 +102,40 @@ returns a negative integer to one of the values defined below.
Unable to parse the loadavg file.
.PP
.BR procps_linux_version ()
returns a positive integer encoding the Linux version if successful. Otherwise
returns a negative integer to one of the values defined below.
.TP
.B -EIO
The procps library was unable to read the osrelease file.
.TP
.B -ERANGE
Unable to parse the osrelease file.
.PP
.BR procps_linux_version ()
may also return any (negated) value that \fBfopen\fR() may set errno to.
.SH FILES
.TP
.I /proc/loadavg
The raw values for load average.
.TP
.I /proc/sys/kernel/osrelease
Contains the release version of the Linux kernel or proc filesystem.
.TP
.I /proc/sys/kernel/pid_max
Contains the value at which PIDs wrap around, one greater than the maximum PID value.
.SH BUGS
Due to the way the three numbers are encoded into a single integer,
.BR procps_linux_version ()
and the associated macros assume 255 for the maximum value for the
minor and patch level and 32767 (hex 0x7fff) for the maximum value
for the major version. In other words, when Linux v 32768.0.0 comes
out, this function will break.
.\" Maj/6yr - In 7452 we'll think of something
.SH SEE ALSO
.BR fopen (3),
.BR sysconf (3),
.BR proc (5).