procps/doc/procps_misc.3
Craig Small 02e35c1fb1 docs: Add procps_misc.3 manpage
The last (I think) of the newlib man pages for the new API.
2020-10-24 18:25:48 +11:00

83 lines
2.8 KiB
Groff

.\" (C) Copyright 2020 Craig Small <csmall@dropbear.xyz>
.\"
.\" %%%LICENSE_START(LGPL_2.1+)
.\" This manual is free software; you can redistribute it and/or
.\" modify it under the terms of the GNU Lesser General Public
.\" License as published by the Free Software Foundation; either
.\" version 2.1 of the License, or (at your option) any later version.
.\"
.\" This manual is distributed in the hope that it will be useful,
.\" but WITHOUT ANY WARRANTY; without even the implied warranty of
.\" MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
.\" Lesser General Public License for more details.
.\"
.\" You should have received a copy of the GNU Lesser General Public
.\" License along with this library; if not, write to the Free Software
.\" Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
.\" %%%LICENSE_END
.\"
.TH PROCPS_MISC 3 2020-10-20 "libproc-2"
.\" Please adjust this date whenever revising the manpage.
.\"
.SH NAME
procps_misc \- API to system information in the /proc filesystem
.SH SYNOPSIS
.nf
.B #include <proc/sysinfo.h>
.PP
.B long procps_cpu_count(void);
.B long procps_hertz_get(void);
.BI "int procps_loadavg(double * " av1 ", double * " av5 ", double * " av15 ");"
.B unsigned int procps_pid_length(void);
.sp
Link with \fI\-lprocps\fP.
.SH DESCRIPTION
.BR procps_cpu_count ()
returns the number of CPUs that are currently online. On most systems returns
the value of
.BI sysconf( _SC_NPROCESSORS_ONLN )
or assumed to be \fI1\fR.
.BR procps_hertz_get ()
returns the number of clock ticks per second. On most systems returns the
value of
.BI sysconf( _SC_CLK_TCK )
or assumed to be \fI100\fR. Divide certain values returned in the
in the \fI/proc\fR filesystem by this value to convert from ticks to seconds.
.BR procps_loadavg ()
Fetches the system load average and puts the 1, 5 and 15 minute averages into
the locations in the given pointers. If the relevant pointer is \fINULL\fR then
.BR procps_loadavg ()
will not set that value.
.BR procps_pid_length ()
Returns the maximum string length for a PID on the system. For example, if the largest
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.
.SH RETURN VALUE
For
.BR procps_cpu_count "() , " procps_hertz_get "() and " procps_pid_length ()
see the \fBDESCRIPTION\fR section for return values.
.BR procps_loadavg ()
returns 0 on success. On failure, it
returns a negative integer to one of the values defined below.
.TP
.B -ERANGE
Unable to parse the loadavg file.
.PP
.SH FILES
.TP
.I /proc/loadavg
The raw values for load average.
.TP
.I /proc/sys/kernel/pid_max
Contains the value at which PIDs wrap around, one greater than the maximum PID value.
.SH SEE ALSO
.BR sysconf (3),
.BR proc (5).