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log10 - Man Page

base-10 logarithmic function


Math library (libm, -lm)


#include <math.h>

double log10(double x);
float log10f(float x);
long double log10l(long double x);

Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

log10f(), log10l():

    _ISOC99_SOURCE || _POSIX_C_SOURCE >= 200112L
        || /* Since glibc 2.19: */ _DEFAULT_SOURCE
        || /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE


These functions return the base-10 logarithm of x.

Return Value

On success, these functions return the base-10 logarithm of x.

For special cases, including where x is 0, 1, negative, infinity, or NaN, see log(3).


See math_error(7) for information on how to determine whether an error has occurred when calling these functions.

For a discussion of the errors that can occur for these functions, see log(3).


For an explanation of the terms used in this section, see attributes(7).

log10(), log10f(), log10l()Thread safetyMT-Safe


C11, POSIX.1-2008.


C99, POSIX.1-2001.

The variant returning double also conforms to SVr4, 4.3BSD, C89.

See Also

cbrt(3), clog10(3), exp10(3), log(3), log2(3), sqrt(3)

Referenced By

exp10(3), log(3), log2(3), unu-1op(1).

The man pages log10f(3) and log10l(3) are aliases of log10(3).

2024-03-12 Linux man-pages 6.7