#include <math.h> double log10(double x);
log10
computes the common (base 10) log of its argument x
.
The x
argument must be a positive double-precision, floating-point number.
log10
returns the common log of its argument, expressed as a
double-precision, floating-point number.
x
is negative or 0, log10
returns -HUGE_VAL
. In this
case, the run-time library also writes an error message to the standard error
file (stderr
).
If an error occurs in log10
, the _matherr
routine is called. You
supply your own version of _matherr
to suppress the diagnostic
message or modify the value returned.
log10
:
#include <math.h> #include <stdio.h> #define RATE .017 main() { double y; y = ceil(log10(RATE)); /* Print the "order of magnitude" of RATE. */ printf("ceil(log10(%f)) = %fn", RATE, y); }
log
, _matherr
Copyright (c) 1998 SAS Institute Inc. Cary, NC, USA. All rights reserved.