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Diffstat (limited to 'man3/get_nprocs.3')
-rw-r--r-- | man3/get_nprocs.3 | 94 |
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diff --git a/man3/get_nprocs.3 b/man3/get_nprocs.3 new file mode 100644 index 0000000..583054d --- /dev/null +++ b/man3/get_nprocs.3 @@ -0,0 +1,94 @@ +'\" t +.\" Copyright (c) 2012, Petr Benas +.\" and Copyright (c) 2012, Michael Kerrisk <mtk.man-pages@gmail.com> +.\" +.\" SPDX-License-Identifier: Linux-man-pages-copyleft +.\" +.TH get_nprocs 3 2023-07-20 "Linux man-pages 6.05.01" +.SH NAME +get_nprocs, get_nprocs_conf \- get number of processors +.SH LIBRARY +Standard C library +.RI ( libc ", " \-lc ) +.SH SYNOPSIS +.nf +.B #include <sys/sysinfo.h> +.PP +.B int get_nprocs(void); +.B int get_nprocs_conf(void); +.fi +.SH DESCRIPTION +The function +.BR get_nprocs_conf () +returns the number of processors configured by the operating system. +.PP +The function +.BR get_nprocs () +returns the number of processors currently available in the system. +This may be less than the number returned by +.BR get_nprocs_conf () +because processors may be offline (e.g., on hotpluggable systems). +.SH RETURN VALUE +As given in DESCRIPTION. +.SH ATTRIBUTES +For an explanation of the terms used in this section, see +.BR attributes (7). +.TS +allbox; +lbx lb lb +l l l. +Interface Attribute Value +T{ +.na +.nh +.BR get_nprocs (), +.BR get_nprocs_conf () +T} Thread safety MT-Safe +.TE +.sp 1 +.SH STANDARDS +GNU. +.SH NOTES +The current +.\" glibc 2.15 +implementation of these functions is rather expensive, +since they open and parse files in the +.I /sys +filesystem each time they are called. +.PP +The following +.BR sysconf (3) +calls make use of the functions documented on this page +to return the same information. +.PP +.in +4n +.EX +np = sysconf(_SC_NPROCESSORS_CONF); /* processors configured */ +np = sysconf(_SC_NPROCESSORS_ONLN); /* processors available */ +.EE +.in +.SH EXAMPLES +The following example shows how +.BR get_nprocs () +and +.BR get_nprocs_conf () +can be used. +.PP +.\" SRC BEGIN (get_nprocs_conf.c) +.EX +#include <stdio.h> +#include <stdlib.h> +#include <sys/sysinfo.h> +\& +int +main(void) +{ + printf("This system has %d processors configured and " + "%d processors available.\en", + get_nprocs_conf(), get_nprocs()); + exit(EXIT_SUCCESS); +} +.EE +.\" SRC END +.SH SEE ALSO +.BR nproc (1) |