MATH(7)                              BSD                               MATH(7)



NAME
     math - math functions and constants

SYNOPSIS
     #include <math.h>

DESCRIPTION
     This file contains declarations of all the functions in the Math Library
     (described in Section 3M), as well as various functions in the C Library
     (Section 3C) that return floating-point values.  It defines the following
     constant, used as an error-return value:

     HUGE_VAL     A positive double expression.  Although Domain/OS BSD
                  currently sets HUGE_VAL equal to FLT_MAX (see limits(5)),
                  HUGE_VAL may not be representable as a float in future
                  implementations.

                  If you require the HUGE macro to be a compile-time constant,
                  add the directive #define _CLASSIC_HUGE before any #include
                  directives.  Programs compiled with _CLASSIC_HUGE are
                  forward-compatible only if linked with /usr/lib/crt0.o.

     <math.h> makes the defining of built-in routines for fabs, sin, cos, tan,
     log, exp, atan, atan2, and sqrt conditional upon your defining the
     _MATH_BUILTINS macro.  See intro(3).

     Which matherr function your program invokes depends upon the startup
     routine to which you link it.  See matherr(3M).

     If you compile with the -A nansi option (see cc(1)), <math.h> defines the
     following mathematical constants for your convenience:

     M_E          The base of natural logarithms (e).

     M_LOG2E      The base-2 logarithm of e.

     M_LOG10E     The base-10 logarithm of e.

     M_LN2        The natural logarithm of 2.

     M_LN10       The natural logarithm of 10.

     M_PI         pi, the ratio of the circumference of a circle to its
                  diameter.

     M_PI_2       pi/2.

     M_PI_4       pi/4.

     M_1_PI       1/pi.

     M_2_PI       2/pi.

     M_2_SQRTPI   2/\/pi.

     M_SQRT2      The positive square root of 2.

     M_SQRT1_2    The positive square root of 1/2.

     If you don't compile with the -A nansi option, <math.h> will define these
     constants for your program if it contains one of the following directives

     (listed in order of increasing restrictiveness) before any #include
     directive:

          #define _APOLLO_SOURCE
          #define _SYS5_SOURCE
          #define _XOPEN_SOURCE

     For the definitions of various machine-dependent "constants," see the
     description of the <values.h> header file.

SEE ALSO
     intro(3), matherr(3M)