'\" t
.\"     Title: bitmap_pos_to_ord
.\"    Author: [FIXME: author] [see http://docbook.sf.net/el/author]
.\" Generator: DocBook XSL Stylesheets v1.79.1 <http://docbook.sf.net/>
.\"      Date: April 2019
.\"    Manual: Basic Kernel Library Functions
.\"    Source: Kernel Hackers Manual 4.9.168
.\"  Language: English
.\"
.TH "BITMAP_POS_TO_ORD" "9" "April 2019" "Kernel Hackers Manual 4\&.9\&." "Basic Kernel Library Functions"
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.SH "NAME"
bitmap_pos_to_ord \- find ordinal of set bit at given position in bitmap
.SH "SYNOPSIS"
.HP \w'int\ bitmap_pos_to_ord('u
.BI "int bitmap_pos_to_ord(const\ unsigned\ long\ *\ " "buf" ", unsigned\ int\ " "pos" ", unsigned\ int\ " "nbits" ");"
.SH "ARGUMENTS"
.PP
\fIbuf\fR
.RS 4
pointer to a bitmap
.RE
.PP
\fIpos\fR
.RS 4
a bit position in
\fIbuf\fR
(0 <=
\fIpos\fR
<
\fInbits\fR)
.RE
.PP
\fInbits\fR
.RS 4
number of valid bit positions in
\fIbuf\fR
.RE
.SH "DESCRIPTION"
.PP
Map the bit at position
\fIpos\fR
in
\fIbuf\fR
(of length
\fInbits\fR) to the ordinal of which set bit it is\&. If it is not set or if
\fIpos\fR
is not a valid bit position, map to \-1\&.
.PP
If for example, just bits 4 through 7 are set in
\fIbuf\fR, then
\fIpos\fR
values 4 through 7 will get mapped to 0 through 3, respectively, and other
\fIpos\fR
values will get mapped to \-1\&. When
\fIpos\fR
value 7 gets mapped to (returns)
\fIord\fR
value 3 in this example, that means that bit 7 is the 3rd (starting with 0th) set bit in
\fIbuf\fR\&.
.PP
The bit positions 0 through
\fIbits\fR
are valid positions in
\fIbuf\fR\&.
.SH "COPYRIGHT"
.br