log10#
Synopsis#
#include <math.h>
double log10(double x);
float log10f(float x);
long double log10l(long double x);
Status#
Partially implemented
Conformance#
IEEE Std 1003.1-2017
Description#
These functions shall compute the base 10 logarithms of their argument x, log10(x)
.
An application wishing to check for error situations should set errno
to zero and call feclearexcept(FE_ALL_EXCEPT)
before calling these functions. On return, if errno
is non-zero or
fetestexcept(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW)
is non-zero, an error has occurred.
Return value#
Upon successful completion, these functions shall return the base 10 logarithms of x.
If x is
±0
, a pole error shall occur andlog10()
,log10f()
, andlog10l()
shall return-HUGE_VAL
,-HUGE_VALF
, and-HUGE_VALL
, respectively.
For finite values of x that are less than 0
, or if x is -Inf
, a domain error shall occur, and either a
NaN
(if supported), or an implementation-defined value shall be returned.
If x is
NaN
, aNaN
shall be returned.If x is
1
,+0
shall be returned.If x is
+Inf
,+Inf
shall be returned.
Errors#
These functions shall fail if:
Domain Error
- The finite value of x is negative, or x is -Inf. If the integer expression(math_errhandling & MATH_ERRNO)
is non-zero, thenerrno
shall be set toEDOM
. If the integer expression(math_errhandling & MATH_ERREXCEPT)
is non-zero, then the invalid floating-point exception shall be raised.Pole Error
- The value of x is zero. If the integer expression(math_errhandling & MATH_ERRNO)
is non-zero, thenerrno
shall be set toERANGE
. If the integer expression(math_errhandling & MATH_ERREXCEPT)
is non-zero, then the divide-by-zero floating-point exception shall be raised.
Tests#
Untested
Known bugs#
None