HP-UX Reference (11i v1 00/12) - 3 Library Functions A-M (vol 6)
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STANDARD Printed by: Nora Chuang [nchuang] STANDARD
/build/1111/BRICK/man3/!!!intro.3c
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log10(3M) log10(3M)
NAME
log10(), log10f() - common logarithm functions
SYNOPSIS
#include <math.h>
double log10(double x);
float log10f(float x);
DESCRIPTION
log10() returns the logarithm base ten of x. The value of x must be greater than zero.
log10f() is a float version of log10(); it takes a float argument and returns a float result. To
use this function, compile either with the default -Ae option or with the -Aa and -D_HPUX_SOURCE
options.
log10f() is not specified by any standard, but it is named in accordance with the conventions specified in
the "Future Library Directions" section of the ANSI C standard.
To use these functions, make sure your program includes <
math.h>, and link in the math library by speci-
fying
-lm on the compiler or linker command line.
Millicode versions of the log10() function are available. Millicode versions of math library functions are
usually faster than their counterparts in the standard library. To use these versions, compile your program
with the +Olibcalls or the +Oaggressive optimization option.
If an error occurs, the millicode versions return the value described in the RETURN VALUE section, but do
not set
errno.
For more information, see the HP-UX Floating-Point Guide.
RETURN VALUE
If x is +INFINITY,
log10() returns +INFINITY.
If x is zero,
log10() returns −HUGE_VAL.
If x is NaN, log10() returns NaN.
If x is less than zero, log10() returns NaN and sets errno to [EDOM].
ERRORS
If log10() fails, errno is set to the following value.
[EDOM] x is less than zero.
SEE ALSO
cbrt(3M), exp(3M), log(3M), log1p(3M), log2(3M), pow(3M), sqrt(3M), math(5).
STANDARDS CONFORMANCE
log10(): SVID3, XPG4.2, ANSI C
Section 3−−496 − 1 − HP-UX Release 11i: December 2000
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