{"id":7349,"date":"2022-12-20T19:37:46","date_gmt":"2022-12-20T22:37:46","guid":{"rendered":"http:\/\/lode.uno\/linux-man\/index.php\/2022\/12\/20\/ffs-man3\/"},"modified":"2022-12-20T19:37:46","modified_gmt":"2022-12-20T22:37:46","slug":"ffs-man3","status":"publish","type":"post","link":"https:\/\/lode.uno\/linux-man\/2022\/12\/20\/ffs-man3\/","title":{"rendered":"FFS (man3)"},"content":{"rendered":"

FFS<\/h1>\n

NAME<\/a>
SYNOPSIS<\/a>
DESCRIPTION<\/a>
RETURN VALUE<\/a>
ATTRIBUTES<\/a>
CONFORMING TO<\/a>
NOTES<\/a>
SEE ALSO<\/a>
COLOPHON<\/a> <\/p>\n

\n

NAME <\/a> <\/h2>\n

ffs, ffsl, ffsll \u2212 find first bit set in a word<\/p>\n

SYNOPSIS <\/a> <\/h2>\n

#include <\/b><\/p>\n

int ffs(int<\/b> i<\/i>);<\/b><\/p>\n

#include <\/b><\/p>\n

int ffsl(long<\/b> i<\/i>);<\/b><\/p>\n

int ffsll(long long<\/b> i<\/i>);<\/b><\/p>\n

Feature Test Macro Requirements for glibc (see feature_test_macros<\/b>(7)):<\/p>\n

ffs<\/b>():<\/p>\n

Since glibc 2.12:<\/p>\n

_XOPEN_SOURCE >= 700
|| ! (_POSIX_C_SOURCE\u00a0>=\u00a0200809L)
|| \/bin \/boot \/dead.letter \/dev \/etc \/home \/initrd \/lib \/lib64 \/lost+found \/media \/mnt \/opt \/proc \/release-notes.html \/release-notes.txt \/root \/run \/sbin \/srv \/sys \/tmp \/usr \/var Glibc since 2.19: bodies\/ usr\/ _DEFAULT_SOURCE
|| \/bin \/boot \/dead.letter \/dev \/etc \/home \/initrd \/lib \/lib64 \/lost+found \/media \/mnt \/opt \/proc \/release-notes.html \/release-notes.txt \/root \/run \/sbin \/srv \/sys \/tmp \/usr \/var Glibc versions <= 2.19: bodies\/ usr\/ _BSD_SOURCE || _SVID_SOURCE<\/p>\n

Before glibc 2.12:<\/p>\n

none<\/p>\n

ffsl<\/b>(), ffsll<\/b>():<\/p>\n

Since glibc 2.27:<\/p>\n

_DEFAULT_SOURCE<\/p>\n

Before glibc 2.27:<\/p>\n

_GNU_SOURCE<\/p>\n

DESCRIPTION <\/a> <\/h2>\n

The ffs<\/b>() function returns the position of the first (least significant) bit set in the word i<\/i>. The least significant bit is position 1 and the most significant position is, for example, 32 or 64. The functions ffsll<\/b>() and ffsl<\/b>() do the same but take arguments of possibly different size.<\/p>\n

RETURN VALUE <\/a> <\/h2>\n

These functions return the position of the first bit set, or 0 if no bits are set in i<\/i>.<\/p>\n

ATTRIBUTES <\/a> <\/h2>\n

For an explanation of the terms used in this section, see attributes<\/b>(7).<\/p>\n\n\n\n
<\/td>\n <\/td>\n <\/td>\n<\/td>\n<\/td>\n <\/td>\n<\/tr>\n
<\/td>\n<\/td>\n <\/td>\n<\/td>\n<\/td>\n <\/td>\n<\/tr>\n<\/table>\n

\"Image<\/p>\n

CONFORMING TO <\/a> <\/h2>\n

ffs<\/b>(): POSIX.1-2001, POSIX.1-2008, 4.3BSD.<\/p>\n

The ffsl<\/b>() and ffsll<\/b>() functions are glibc extensions.<\/p>\n

NOTES <\/a> <\/h2>\n

BSD systems have a prototype in <\/i>.<\/p>\n

SEE ALSO <\/a> <\/h2>\n

memchr<\/b>(3)<\/p>\n

COLOPHON <\/a> <\/h2>\n

This page is part of release 5.10 of the Linux man-pages<\/i> project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at https:\/\/www.kernel.org\/doc\/man\u2212pages\/.<\/p>\n

\n","protected":false},"excerpt":{"rendered":"

ffs, ffsl, ffsll \u2212 find first bit set in a word <\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[2536],"tags":[2538,1685,3007],"class_list":["post-7349","post","type-post","status-publish","format-standard","hentry","category-3-llamadas-de-bibliotecas","tag-2538","tag-ffs","tag-man3"],"gutentor_comment":0,"_links":{"self":[{"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/posts\/7349","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/comments?post=7349"}],"version-history":[{"count":0,"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/posts\/7349\/revisions"}],"wp:attachment":[{"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/media?parent=7349"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/categories?post=7349"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/lode.uno\/linux-man\/wp-json\/wp\/v2\/tags?post=7349"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}