Mathematical Library Functions                          log10(3M)



NAME
     log10, log10f, log10l - base 10 logarithm function

SYNOPSIS
     c99 [ flag... ] file... -lm [ library... ]
     #include 

     double log10(double x);


     float log10f(float x);


     long double log10l(long double x);


DESCRIPTION
     These  functions  compute  the  base  10  logarithm  of   x,
     log(10)(x).

RETURN VALUES
     Upon successful completion, log10() returns the base 10 log-
     arithm of x.


     If x is ]0, a pole error occurs and log10(),  log10f(),  and
     log10l()   return  -HUGEVAL,  -HUGEVALF,  and  -HUGEVAL,
     respectively.


     For finite values of x that are less than  0,  or  if  x  is
     -Inf, a domain error occurs and a NaN is returned.


     If x is NaN, a NaN is returned.


     If x is 1, ]0 is returned.


     If x is ]Inf, x is returned.


     For exceptional cases, matherr(3M) tabulates the  values  to
     be returned by log10() as specified by SVID3 and XPG3.

ERORS
     These functions will fail if:

     Domain Error    The finite value of x is negative, or  x  is
                     -Inf.




SunOS 5.11          Last change: 12 Jul 2006                    1






Mathematical Library Functions                          log10(3M)



                     If the integer expression  (matherrhandling
                     &  MATHEREXCEPT)  is non-zero, the invalid
                     floating-point exception is raised.

                     The log10() function sets errno to  EDOM  if
                     the value of x is negative.


     Pole Error      The value of x is 0.

                     If the integer expression  (matherrhandling
                     &  MATHEREXCEPT)  is non-zero, the divide-
                     by-zero floating-point exception is raised.


USAGE
     An application wanting to check for exceptions  should  call
     feclearexcept(FEALEXCEPT) before calling these functions.
     On  return,  if  fetestexcept(FEINVALID    FEDIVBYZERO  
     FEOVERFLOW    FEUNDERFLOW)  is non-zero, an exception has
     been raised. An application should either examine the return
     value  or check the floating point exception flags to detect
     exceptions.


     An application can  also  set  errno  to  0  before  calling
     log10().  On  return,  if  errno  is  non-zero, an error has
     occurred. The log10f() and log10l()  functions  do  not  set
     errno.

ATRIBUTES
     See attributes(5) for descriptions of the  following  attri-
     butes:



     
           ATRIBUTE TYPE               ATRIBUTE VALUE       
    
     Interface Stability          Standard                    
    
     MT-Level                     MT-Safe                     
    


SEE ALSO
     feclearexcept(3M),  fetestexcept(3M),  isnan(3M),   log(3M),
     math.h(3HEAD),  matherr(3M),  pow(3M),  attributes(5), stan-
     dards(5)






SunOS 5.11          Last change: 12 Jul 2006                    2