log10 man page

log10, log10f, log10l — base-10 logarithmic function


#include <math.h>

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

Link with -lm.

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

log10f(), log10l():

   || /* Since glibc 2.19: */ _DEFAULT_SOURCE
   || /* Glibc versions <= 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).

Interface Attribute Value
log10(), log10f(), log10l() Thread safety MT-Safe

Conforming to

C99, POSIX.1-2001, POSIX.1-2008.

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)


This page is part of release 4.15 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.

Referenced By

exp10(3), log(3), log2(3).

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

2017-09-15 Linux Programmer's Manual