Computes the Base 10 logarithm.
#include <math.h> float log10f (x) float x; long double log10l (x) long double x; double log10 (x) double x;
The log10f, log10l, and log10 subroutines compute the base 10 logarithm of the x parameter, log10 (x).
An application wishing to check for error situations should set errno to zero and call feclearexcept(FE_ALL_EXCEPT) before calling these subroutines. Upon return, if errno is nonzero or fetestexcept(FE_INVALID | FE_DIVBYZERO | FE_OVERFLOW | FE_UNDERFLOW) is nonzero, an error has occurred.
| x | Specifies the value to be computed. |
Upon successful completion, the log10, log10f, and log10l, subroutines return the base 10 logarithm of x.
If x is ±0, a pole error occurs and log10, log10f, and log10l subroutines 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 occurs, and a NaN is returned.
If x is NaN, a NaN is returned.
If x is 1, +0 is returned.
If x is +Inf, +Inf is returned.
When using the libm.a library:
| log10 | If the x parameter is less than 0, the log10 subroutine returns a NaNQ value and sets errno to EDOM. If x= 0, the log10 subroutine returns a -HUGE_VAL value but does not modify errno. |
When using libmsaa.a(-lmsaa):
| log10 | If the x parameter is not positive, the log10 subroutine returns a -HUGE_VAL value and sets errno to EDOM. A message indicating DOMAIN error (or SING error when x = 0) is output to standard error. |
| log10 | If x < 0, log10l returns the value NaNQ and sets errno to EDOM. If x equals 0, log10l returns the value -HUGE_VAL but does not modify errno. |
feclearexcept Subroutine, fetestexcept Subroutine, class, _class, finite, isnan, or unordered Subroutines, and madd, msub, mult, mdiv, pow, gcd, invert, rpow, msqrt, mcmp, move, min, omin, fmin, m_in, mout, omout, fmout, m_out, sdiv, or itom Subroutine.
math.h in AIX 5L Version 5.2 Files Reference.