Defined in header <math.h> | ||
|---|---|---|
float log10f( float arg ); | (1) | (since C99) |
double log10( double arg ); | (2) | |
long double log10l( long double arg ); | (3) | (since C99) |
Defined in header <tgmath.h> | ||
#define log10( arg ) | (4) | (since C99) |
arg.arg has type long double, log10l is called. Otherwise, if arg has integer type or the type double, log10 is called. Otherwise, log10f is called.| arg | - | floating point value |
If no errors occur, the common (base-10) logarithm of arg (log10(arg) or lg(arg)) is returned.
If a domain error occurs, an implementation-defined value is returned (NaN where supported).
If a pole error occurs, -HUGE_VAL, -HUGE_VALF, or -HUGE_VALL is returned.
Errors are reported as specified in math_errhandling.
Domain error occurs if arg is less than zero.
Pole error may occur if arg is zero.
If the implementation supports IEEE floating-point arithmetic (IEC 60559),
FE_DIVBYZERO is raised. FE_INVALID is raised. #include <stdio.h>
#include <math.h>
#include <float.h>
#include <errno.h>
#include <fenv.h>
// #pragma STDC FENV_ACCESS ON
int main(void)
{
printf("log10(1000) = %f\n", log10(1000));
printf("log10(0.001) = %f\n", log10(0.001));
printf("base-5 logarithm of 125 = %f\n", log10(125)/log10(5));
// special values
printf("log10(1) = %f\n", log10(1));
printf("log10(+Inf) = %f\n", log10(INFINITY));
//error handling
errno = 0; feclearexcept(FE_ALL_EXCEPT);
printf("log10(0) = %f\n", log10(0));
if(errno == ERANGE) perror(" errno == ERANGE");
if(fetestexcept(FE_DIVBYZERO)) puts(" FE_DIVBYZERO raised");
}Possible output:
log10(1000) = 3.000000
log10(0.001) = -3.000000
base-5 logarithm of 125 = 3.000000
log10(1) = 0.000000
log10(+Inf) = inf
log10(0) = -inf
errno == ERANGE: Numerical result out of range
FE_DIVBYZERO raised|
(C99)(C99) | computes natural (base-e) logarithm (\({\small \ln{x} }\)ln(x)) (function) |
|
(C99)(C99)(C99) | computes base-2 logarithm (\({\small \log_{2}{x} }\)log2(x)) (function) |
|
(C99)(C99)(C99) | computes natural (base-e) logarithm of 1 plus the given number (\({\small \ln{(1+x)} }\)ln(1+x)) (function) |
C++ documentation for log10 |
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