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docs: adapt procps_misc.3 for new 'misc.h' header file
This commit adapts our man page for a new consolidated 'misc.h' header file. Along the way, some descriptions were shortened, others lengthened and whitespace added in an effort to (hopefully) improve readability a bit. [ the #include subdirectory was also corrected while ] [ rearranging & grouping functions into 3 categories ] Signed-off-by: Jim Warner <james.warner@comcast.net>
This commit is contained in:
Jim Warner
Craig Small
parent
423297c9db
commit
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@ -1,4 +1,5 @@
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.\" (C) Copyright 2020 Craig Small <csmall@dropbear.xyz>
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.\" (C) Copyright 2021 Jim Warner <warnerjc@comcast.net>
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.\"
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.\" %%%LICENSE_START(LGPL_2.1+)
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.\" This manual is free software; you can redistribute it and/or
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@ -16,169 +17,128 @@
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.\" Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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.\" %%%LICENSE_END
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.\"
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.TH PROCPS_MISC 3 2020-12-21 "libproc-2"
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.TH PROCPS_MISC 3 "January 2021" "libproc-2"
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.\" Please adjust this date whenever revising the manpage.
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.\"
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.nh
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.SH NAME
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procps_misc \- API to system information in the /proc filesystem
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procps_misc \- API for miscellaneous information in the /proc filesystem
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.SH SYNOPSIS
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.nf
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.B #include <proc/namespace.h>
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.B #include <procps/misc.h>
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.PP
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.BI "int procps_ns_get_id(const char * " name ");"
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.BI "const char *procps_ns_get_name(const int " id ");"
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.BI "int procps_ns_read_pid(const int " pid ", struct procps_namespaces * " nsp ");"
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.PP
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.B #include <proc/sysinfo.h>
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.PP
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.B long procps_cpu_count(void);
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.B long procps_hertz_get(void);
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.BI "int procps_loadavg(double * " av1 ", double * " av5 ", double * " av15 ");"
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.B unsigned int procps_pid_length(void);
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.PP
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.B #include <proc/uptime.h>
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.PP
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.BI "int procps_uptime(double * " uptime_secs ", double * " idle_secs ");"
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.B char *procps_uptime_sprint(void);
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.B char *procps_uptime_sprint_short(void);
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.PP
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.B #include <proc/version.h>
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.PP
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.B int procps_linux_version(void);
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.sp
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Link with \fI\-lprocps\fP.
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.SH DESCRIPTION
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This manual page describes the miscellaneous API functions of the
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.B procps
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library.
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.BR procps_cpu_count ()
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returns the number of CPUs that are currently online. On most systems returns
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the value of
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.BI sysconf( _SC_NPROCESSORS_ONLY )
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or assumed to be \fI1\fR.
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.BR procps_hertz_get ()
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returns the number of clock ticks per second. On most systems returns the
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value of
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.BI sysconf( _SC_CLK_TCK )
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or assumed to be \fI100\fR. Divide certain values returned in the
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in the \fI/proc\fR filesystem by this value to convert from ticks to seconds.
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.BR procps_loadavg ()
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Fetches the system load average and puts the 1, 5 and 15 minute averages into
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the locations in the given pointers. If the relevant pointer is \fINULL\fR then
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.BR procps_loadavg ()
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will not set that value.
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.BR procps_pid_length ()
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Returns the maximum string length for a PID on the system. For example, if the largest
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possible PID value on was 123, then the length would be 3. If the file
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\fI/proc/sys/kernel/pid_max\fR is unreadable, the value is assumed to be \fI5\fR.
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.BR procps_linux_version ()
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returns the current Linux version as an integer. On non-Linux systems that
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have an emulated proc filesystem this function returns the version of the
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Linux emulation instead.
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The Linux version consists of a triple of positive integers representing
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the major, minor and patch versions of the kernel.
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.PP
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The library provides 3 macros for separating out the components.
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Platform Particulars
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.RS 4
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.TP 1.2i
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.BR LINUX_VERSION_MAJOR (ver)
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Extract the major component from the given version integer.
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.TP
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.BR LINUX_VERSION_MINOR (ver)
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Extract the minor component from the given version integer.
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.TP
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.BR LINUX_VERSION_PATCH (ver)
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Extract the patch component from the given version integer.
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.PP
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.B "long procps_cpu_count (void);"
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.B "long procps_hertz_get (void);"
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.B "unsigned int procps_pid_length (void);"
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.B "int procps_linux_version (void);"
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.RE
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.PP
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To encode a given Linux version, such as using it to compare against the current
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version, use the following macro:
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.TP
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.BI LINUX_VERSION( major , minor , patch )
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Runtime Particulars
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.PP
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.BR procps_uptime ()
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returns the uptime and idle time of the system. Either the
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\fIuptime_secs\fR or \fIidle_secs\fR can be \fBNULL\fR in which case that
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variable will not be returned.
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.RS 4
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.BI "int procps_loadavg (double * " av1 ", double * " av5 ", double * " av15 ");"
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.BI "int procps_uptime (double * " uptime_secs ", double * " idle_secs ");"
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.B "char * procps_uptime_sprint (void);"
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.B "char * procps_uptime_sprint_short (void);"
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.RE
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.PP
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Namespace Particulars
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.PP
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.RS 4
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.BI "int procps_ns_get_id (const char * " name ");"
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.BI "const char * procps_ns_get_name (int " id ");"
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.BI "int procps_ns_read_pid (int " pid ", struct procps_ns * " nsp ");"
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.RE
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.sp
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Link with \fI\-lprocps\fP.
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The \fBsprint\fR variety of the functions return a human-readable
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string of the uptime and other statistics.
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.SH DESCRIPTION
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.BR procps_cpu_count ()
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returns the number of CPUs that are currently online as
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.BI sysconf( _SC_NPROCESSORS_ONLY )
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or an assumed \fI1\fR.
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.BR procps_ns_get_id ()
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finds the ID of the namespace for the given namespace name.
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.BR procps_hertz_get ()
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returns the number of clock ticks per second as
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.BI sysconf( _SC_CLK_TCK )
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or an assumed \fI100\fR.
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Dividing tics by this value yields seconds.
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.BR procps_ns_get_name ()
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finds the name of the namespace of the given integer ID.
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.BR procps_pid_length ()
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returns the maximum string length for a PID on the system. For example, if the largest
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possible PID value on was 123, then the length would be 3. If the file
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\fI/proc/sys/kernel/pid_max\fR is unreadable, the value is assumed to be \fI5\fR.
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.BR procps_ns_read_pid ()
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puts the inodes for the namespaces of the given process into
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the array pointed to \fInsp\fR.
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.SH RETURN VALUE
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For
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.BR procps_cpu_count "() , " procps_hertz_get "() and " procps_pid_length ()
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see the \fBDESCRIPTION\fR section for return values.
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.BR procps_linux_version ()
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returns the current Linux version as an encoded integer. On non-Linux systems that
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have an emulated proc filesystem this function returns the version of the
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Linux emulation instead.
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The version consists of three positive integers representing the major,
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minor and patch levels.
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The following macros are provided for encoding a given Linux version or
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separating out the components of the current version.
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.RS 4
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.PP
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LINUX_VERSION(\ major\ ,\ minor\ ,\ patch\ )
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.PP
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LINUX_VERSION_MAJOR(\ ver\ )
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.PP
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LINUX_VERSION_MINOR(\ ver\ )
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.PP
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LINUX_VERSION_PATCH(\ ver\ )
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.RE
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.BR procps_loadavg ()
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returns 0 on success. On failure, it
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returns a negative integer to one of the values defined below.
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.TP
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.B -ERANGE
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Unable to parse the loadavg file.
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.PP
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fetches the system load average and puts the 1, 5 and 15 minute averages into
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location(s) specified by any pointer which is not \fINULL\fR.
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.BR procps_linux_version ()
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returns a positive integer encoding the Linux version if successful. Otherwise
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returns a negative integer to one of the values defined below.
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.TP
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.B -EIO
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The procps library was unable to read the osrelease file.
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.TP
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.B -ERANGE
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Unable to parse the osrelease file.
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.BR procps_uptime ()
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returns uptime and/or idle seconds into location(s) specified by any pointer
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which is not \fINULL\fR.
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The \fBsprint\fR varieties return a human-readable string in one of two forms.
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.RS 4
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.PP
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.BR procps_linux_version ()
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may also return any (negated) value that \fBfopen\fR() may set errno to.
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HH:MM:SS up HH:MM, # users, load average: 1, 5, 15 MM averages
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.PP
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up HH, MM
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.RE
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.BR procps_ns_get_id ()
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returns an integer for the namespace ID for the given name or
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.B \-EINVAL
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for an invalid input or an unknown namespace name.
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returns the integer id (enum namespace_type) of the namespace for the given namespace \fIname\fR.
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.BR procps_ns_get_name ()
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returns a statically allocated string containing the name of the
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namespace for the given ID. If the name is not found the function
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returns
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.B NULL
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returns the name of the namespace for the given \fIid\fR (enum namespace_type).
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.BR procps_ns_read_pid ()
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Returns 0 on success and \fB\-EINVAL\fR on failure.
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.BR procps_uptime ()
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returns 0 on success. On failure, it
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returns a negative integer to one of the values defined below.
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.TP
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.B -ERANGE
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Unable to parse the uptime file.
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returns the inodes for the namespaces of the given process in the
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procps_ns structure pointed to by \fInsp\fR.
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Those inodes will appear in the order proscribed by enum namespace_type.
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.PP
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.BR procps_uptime ()
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may also return any (negated) value that \fBfopen\fR() may set errno to.
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.RS 4
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.nf
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enum namespace_type {
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PROCPS_NS_IPC,
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PROCPS_NS_MNT,
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PROCPS_NS_NET,
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PROCPS_NS_PID,
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PROCPS_NS_USER,
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PROCPS_NS_UTS
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};
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.fi
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.RE
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.BR procps_uptime_sprint_short ()
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return a string from a statically allocated buffer which displays uptime.
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.BR procps_uptime_sprint ()
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also displays users and load average in the buffer. The formats are the
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same as
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.BR uptime (1)
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with and without the
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.B \-p
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option.
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.SH RETURN VALUE
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.SS Functions Returning an `int' or `long'
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An error will be indicated by a negative number that
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is always the inverse of some well known errno.h value.
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.SS Functions Returning an `address'
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An error will be indicated by a NULL return pointer
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with the reason found in the formal errno value.
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.SH FILES
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.TP
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@ -194,20 +154,10 @@ Contains the value at which PIDs wrap around, one greater than the maximum PID v
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.I /proc/uptime
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The raw values for uptime and idle time.
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.TP
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.IB /proc/ PID /ns
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.IB /proc/<PID>/ns
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contains the set of namespaces for a particular \fBPID\fR.
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.SH BUGS
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Due to the way the three numbers are encoded into a single integer,
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.BR procps_linux_version ()
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and the associated macros assume 255 for the maximum value for the
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minor and patch level and 32767 (hex 0x7fff) for the maximum value
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for the major version. In other words, when Linux v 32768.0.0 comes
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out, this function will break.
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.\" Maj/6yr - In 7452 we'll think of something
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.SH SEE ALSO
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.BR uptime (1),
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.BR fopen (3),
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.BR sysconf (3),
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.BR procps (3).
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.BR procps_pids (3).
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.BR proc (5).
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