LOG(3) | Library Functions Manual | LOG(3) |
log
, logf
,
log10
, log10f
,
log1p
, log1pf
,
log2
, log2f
—
#include <math.h>
double
log
(double
x);
float
logf
(float
x);
double
log10
(double
x);
float
log10f
(float
x);
double
log1p
(double
x);
float
log1pf
(float
x);
double
log2
(double
x);
float
log2f
(float
x);
log
() and logf
()
functions return the natural logarithm.log10
() and log10f
()
functions return the base 10 logarithm.log1p
() and log1pf
()
functions return the natural logarithm of (1.0 + x)
accurately even for very small values of x.log2
() and log2f
()
functions return the base 2 logarithm.log
(), log10
(), and
log2
() families return either
-HUGE_VAL
, -HUGE_VALF
, or
-HUGE_VALL
, whereas the
log1p
() family returns
x.log
(),
log10
(), and log2
()
families return +0.0. If x is -1.0, the
log1p
() family returns
-HUGE_VAL
, -HUGE_VALF
, or
-HUGE_VALL
.In addition, on a VAX, errno is set to
EDOM
and the reserved operand is returned by
log
() unless x > 0, by
log1p
() unless x > -1.
log
() function appeared in
Version 1 AT&T UNIX.
September 2, 2019 | NetBSD 9.0 |