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| author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-15 19:40:15 +0000 |
|---|---|---|
| committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-04-15 19:40:15 +0000 |
| commit | 399644e47874bff147afb19c89228901ac39340e (patch) | |
| tree | 1c4c0b733f4c16b5783b41bebb19194a9ef62ad1 /man3/powerof2.3 | |
| parent | Initial commit. (diff) | |
| download | manpages-399644e47874bff147afb19c89228901ac39340e.tar.xz manpages-399644e47874bff147afb19c89228901ac39340e.zip | |
Adding upstream version 6.05.01.upstream/6.05.01
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to '')
| -rw-r--r-- | man3/powerof2.3 | 46 |
1 files changed, 46 insertions, 0 deletions
diff --git a/man3/powerof2.3 b/man3/powerof2.3 new file mode 100644 index 0000000..fae024f --- /dev/null +++ b/man3/powerof2.3 @@ -0,0 +1,46 @@ +.\" Copyright (C) 2022 Alejandro Colomar <alx@kernel.org> +.\" +.\" SPDX-License-Identifier: Linux-man-pages-copyleft +.\" +.TH powerof2 3 2023-03-30 "Linux man-pages 6.05.01" +.SH NAME +powerof2 \- test if a value is a power of 2 +.SH LIBRARY +Standard C library +.RI ( libc ) +.SH SYNOPSIS +.nf +.B #include <sys/param.h> +.PP +.BI "int powerof2(" x ); +.fi +.SH DESCRIPTION +This macro returns true if +.I x +is a power of 2, +and false otherwise. +.PP +.B 0 +is considered a power of 2. +This can make sense considering wrapping of unsigned integers, +and has interesting properties. +.SH RETURN VALUE +True or false, +if +.I x +is a power of 2 or not, +respectively. +.SH STANDARDS +BSD. +.SH CAVEATS +The arguments may be evaluated more than once. +.PP +Because this macro is implemented using bitwise operations, +some negative values can invoke undefined behavior. +For example, +the following invokes undefined behavior: +.IR "powerof2(INT_MIN);". +Call it only with unsigned types to be safe. +.SH SEE ALSO +.BR stdc_bit_ceil (3), +.BR stdc_bit_floor (3) |