ack/lang/cem/libcc.ansi/core/math/log10.c
David Given d1cdb07719 Realise that the libc core can safely call other libc core functions, even if
they're not defined in the core: so putw() can call stdio stuff, for example.
So the earlier concept of pureness isn't necessary. Rename accordingly.
2018-06-21 23:24:23 +02:00

34 lines
490 B
C

/*
* (c) copyright 1988 by the Vrije Universiteit, Amsterdam, The Netherlands.
* See the copyright notice in the ACK home directory, in the file "Copyright".
*
* Author: Ceriel J.H. Jacobs
*/
/* $Id$ */
#include <math.h>
#include <errno.h>
#include "localmath.h"
double
log10(double x)
{
if (__IsNan(x))
{
errno = EDOM;
return x;
}
if (x < 0)
{
errno = EDOM;
return -HUGE_VAL;
}
else if (x == 0)
{
errno = ERANGE;
return -HUGE_VAL;
}
return log(x) / M_LN10;
}