| 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 10.0 |