Index for Section 3

Alphabetical listing for E

exp(3)
NAME
  exp, expm1, log, log2, log10, log1p, pow - Exponential, logarithm, and
  power functions

LIBRARY
  Math Library (libm.a)

SYNOPSIS
  #include <math.h>

  double exp	(double x);
  float	 expf	(float	x);
  double expm1	(double x);
  float	 expm1f (float	x);
  double log	(double x);
  float	 logf	(float	x);
  double log2	(double x);
  float	 log2f	(float	x);
  double log10	(double x);
  float	 log10f (float	x);
  double log1p	(double y);
  float	 log1pf (float	y);
  double pow	(double x, double y);
  float	 powf	(float	x, float  y);

STANDARDS
  Interfaces documented on this reference page conform to industry standards
  as follows:

  exp():  XPG4

  expm1():  XPG4-UNIX

  log():  XPG4

  log10():  XPG4

  log1p():  XPG4-UNIX

  pow():  XPG4

  Refer to the standards(5) reference page for more information about
  industry standards and associated tags.

DESCRIPTION
  The exp() and expf() functions compute the value of the exponential
  function, defined as e**x, where e is the constant used as a base for
  natural logarithms.

  The expm1() and expm1f() functions compute exp(x) - 1 accurately, even for
  tiny x.

  The log() and logf() functions compute the natural (base e) logarithm of x.

  The log2() and log2f() functions compute the base 2 logarithm of x.

  The log10() and log10f() functions compute the common (base 10) logarithm
  of x.

  The log1p() and log1pf() functions compute log(1+y) accurately, even for
  tiny y.

  The pow() and powf() functions raise a floating-point base x to a
  floating-point exponent y. The value of pow(x,y) is computed as e**(y
  ln(x)) for positive x.  If x is 0 or negative, see your language reference
  manual.

  Passing a NaN input value to pow() produces a NaN result for y not equal to
  0. For pow(NaN,0), see your language reference manual.

  The following table describes function behavior in response to exceptional
  arguments:

  ______________________________________________________________
  Function	      Exceptional Argument	Routine Behavior
  ______________________________________________________________
  exp(), expf()	      x > ln(max_float)		Overflow
  exp(), expf()	      x < ln(min_float)		Underflow
  expm1(), expm1f()   x > ln(max_float)		Overflow
  expm1(), expm1f()   x < ln(min_float)		Underflow
  log(), logf()	      x < 0			Invalid argument
  log(), logf()	      x = 0			Overflow
  log2(), log2f()     x < 0			Invalid argument
  log2(), logf2()     x = 0			Overflow
  log10(), log10f()   x < 0			Invalid argument
  log10(), log10f()   x = 0			Overflow
  log1p(), log1pf()   1+y < 0			Invalid argument
  log1p(), log1pf()   1+y = 0			Overflow
  pow(), powf()	      y ln(x) > ln(max_float)	Overflow
  pow(), powf()	      y ln(x) < ln(min_float)	Underflow
  ______________________________________________________________

  The following table lists boundary values used by these functions:
  ____________________________________________________________________________
  Value		      Data	     Hexadecimal Value	    Decimal Value
  Name		      Type
  ____________________________________________________________________________
  ln(max_float)	      S_FLOAT	     42B17218		    88.7228391
		      T_FLOAT	     40862E42FEFA39EF	    709.7827128933840
  ln(min_float)	      S_FLOAT	     C2CE8ED0		    -103.2789
		      T_FLOAT	     C0874385446D71C3	    -744.4400719213813
  ____________________________________________________________________________