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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-24 04:52:24 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-24 04:52:24 +0000 |
commit | 100d1b33f088fd38f69129afff7f9c2a1e084a57 (patch) | |
tree | 5bf6b0bb14f22ecf0a5e9439fdd4c4758402400c /man/man3/arc4random.3 | |
parent | Releasing progress-linux version 6.7-2~progress7.99u1. (diff) | |
download | manpages-100d1b33f088fd38f69129afff7f9c2a1e084a57.tar.xz manpages-100d1b33f088fd38f69129afff7f9c2a1e084a57.zip |
Merging upstream version 6.8.
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'man/man3/arc4random.3')
-rw-r--r-- | man/man3/arc4random.3 | 109 |
1 files changed, 109 insertions, 0 deletions
diff --git a/man/man3/arc4random.3 b/man/man3/arc4random.3 new file mode 100644 index 0000000..44e6674 --- /dev/null +++ b/man/man3/arc4random.3 @@ -0,0 +1,109 @@ +'\" t +.\" Copyright (C) 2023 Alejandro Colomar <alx@kernel.org> +.\" +.\" SPDX-License-Identifier: Linux-man-pages-copyleft +.\" +.TH arc4random 3 2024-05-02 "Linux man-pages (unreleased)" +.SH NAME +arc4random, arc4random_uniform, arc4random_buf +\- cryptographically-secure pseudorandom number generator +.SH LIBRARY +Standard C library +.RI ( libc ", " \-lc ) +.SH SYNOPSIS +.nf +.B #include <stdlib.h> +.P +.B uint32_t arc4random(void); +.BI "uint32_t arc4random_uniform(uint32_t " upper_bound ); +.BI "void arc4random_buf(void " buf [. n "], size_t " n ); +.fi +.SH DESCRIPTION +These functions give cryptographically-secure pseudorandom numbers. +.P +.BR arc4random () +returns a uniformly-distributed value. +.P +.BR arc4random_uniform () +returns a uniformly-distributed value less than +.I upper_bound +(see BUGS). +.P +.BR arc4random_buf () +fills the memory pointed to by +.IR buf , +with +.I n +bytes of pseudorandom data. +.P +The +.BR rand (3) +and +.BR drand48 (3) +families of functions should only be used where +the quality of the pseudorandom numbers is not a concern +.I and +there's a need for repeatability of the results. +Unless you meet both of those conditions, +use the +.BR arc4random () +functions. +.SH RETURN VALUE +.BR arc4random () +returns a pseudorandom number. +.P +.BR arc4random_uniform () +returns a pseudorandom number less than +.I upper_bound +for valid input, or +.B 0 +when +.I upper_bound +is invalid. +.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 arc4random (), +.BR arc4random_uniform (), +.BR arc4random_buf () +T} Thread safety MT-Safe +.TE +.SH STANDARDS +BSD. +.SH HISTORY +OpenBSD 2.1, +FreeBSD 3.0, +NetBSD 1.6, +DragonFly 1.0, +libbsd, +glibc 2.36. +.SH BUGS +An +.I upper_bound +of +.B 0 +doesn't make sense in a call to +.BR arc4random_uniform (). +Such a call will fail, and return +.BR 0 . +Be careful, +since that value is +.I not +less than +.IR upper_bound . +In some cases, +such as accessing an array, +using that value could result in Undefined Behavior. +.SH SEE ALSO +.BR getrandom (3), +.BR rand (3), +.BR drand48 (3), +.BR random (7) |