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fmod(3)
NAME
  fmod, drem, remainder - Compute the floating-point remainder

LIBRARY
  Math Library (libm.a)

SYNOPSIS
  #include <math.h>

  double       fmod	  (double x, double y);
  float	       fmodf	  (float  x, float  y);
  double       drem	  (double x, double y);
  float	       dremf	  (float  x, float  y);
  double       remainder  (double x, double y);
  float	       remainderf (float  x, float  y);

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

  fmod():  XPG4

  remainder():	XPG4-UNIX

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

DESCRIPTION
  The fmod() and fmodf() functions return the remainder	 r = x - n*y, where n
  = trunc(x/y).	 The result has the same sign as x and magnitude less than
  the magnitude of y.  The remainder is computed exactly and |r| is less than
  or equal to |y|/2.

  The drem(), dremf(), remainder(), and remainderf() functions return the
  remainder r = x - n*y, where n = rint(x/y).  Additionally, if |n -
  x/y|=1/2, then n is even.  The remainder is computed exactly and |r| is
  less than or equal to |y|/2.

  The drem() and remainder() functions are aliases of each other.  The
  dremf(), and remainderf() functions are aliases of each other.

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

  _________________________________________________________________
  Function		 Exceptional Argument	   Routine Behavior
  _________________________________________________________________
  fmod(),  fmodf()	 x = infinity		   Invalid argument
  fmod(),  fmodf()	 y = 0			   Invalid argument
  drem(),  dremf()	 x = infinity		   Invalid argument
  drem(),  dremf()	 y = 0			   Invalid argument
  remainder()		 x = infinity		   Invalid argument
  remainderf()		 x = infinity		   Invalid argument
  remainder()		 y = 0			   Invalid argument
  remainderf()		 y = 0			   Invalid argument
  _________________________________________________________________