NAME
roundup —
macros for counting and
rounding
SYNOPSIS
#include
<sys/param.h>
size
howmany(x,
size);
size
roundup(x,
size);
size
rounddown(x,
size);
size
roundup2(x,
size);
int
powerof2(x);
DESCRIPTION
Theroundup()
and
rounddown()
macros return an integer from rounding x up and down,
respectively, to the next size. The
howmany()
macro in turn reveals how many times size fits into
x, rounding the residual up.
The
roundup2()
macro also rounds up, but with the assumption that
size is a power of two. If x is
indeed a power of two,
powerof2()
return 1.
RETURN VALUES
The return value is an integer from the respective operation. If
x is 0, all macros except
powerof2() return 0. The behavior is undefined if
size is 0.
EXAMPLES
The following example rounds the variable rx to a 32-bit boundary:
uint16_t rx; ... rx = roundup2(rx, sizeof(uint32_t));
SEE ALSO
CAVEATS
All described macros make no assumptions about the type of the parameters. These are implicitly assumed to be unsigned integers.