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Mathematical Functions

The mathematical functions include a large proportion of the floating-point math functions usually provided with traditional UNIX C compilers. The header file <math.h> should be included when using most of these functions. See the individual function descriptions to determine whether the header file is required for that function.

The library also provides the standard header file <float.h> , which provides additional information about floating-point arithmetic. The contents of this header file are listed here: 

#define FLT_RADIX 16          /* hardware float radix               */
#define FLT_ROUNDS 0          /* float addition does not round.     */

#define FLT_MANT_DIG 6        /* hex digits in float mantissa       */
#define DBL_MANT_DIG 14       /* hex digits in double mantissa      */
#define LDBL_MANT_DIG 14      /* hex digits in long double mantissa */

#define FLT_DIG 6             /* float decimal precision            */
#define DBL_DIG 16            /* double decimal precision           */
#define LDBL_DIG 16           /* long double decimal precision      */

#define FLT_MIN_EXP -64       /* minimum exponent of 16 for float   */
#define DBL_MIN_EXP -64       /* minimum exponent of 16 for double  */
#define LDBL_MIN_EXP -64      /* minimum exponent of 16 for long    */
                              /* double                             */

#define FLT_MIN_10_EXP -78    /* minimum float power of 10          */
#define DBL_MIN_10_EXP -78    /* minimum double power of 10         */
#define LDBL_MIN_10_EXP -78   /* minimum long double power of 10    */

#define FLT_MAX_EXP 63        /* maximum exponent of 16 for float   */
#define DBL_MAX_EXP 63        /* maximum exponent of 16 for double  */
#define LDBL_MAX_EXP 63       /* maximum exponent of 16 for long    */
                              /* double                             */
#define FLT_MAX_10_EXP 75     /* maximum float power of 10          */
#define DBL_MAX_10_EXP 75     /* maximum double power of 10         */
#define LDBL_MAX_10_EXP 75    /* maximum long double power of 10    */

#define FLT_MAX .7237005e76F              /* maximum float          */
#define DBL_MAX .72370055773322621e76     /* maximum double         */
#define LDBL_MAX .72370055773322621e76L   /* maximum long double    */

   /* smallest float x such that 1.0 + x != 1.0                     */
#define FLT_EPSILON .9536743e-6F

   /* smallest double x such that 1.0 + x != 1.0                    */
#define DBL_EPSILON .22204460492503131e-15

   /* smallest long double x such that 1.0 - x != 1.0               */
#define LDBL_EPSILON .22204460492503131e-15L

#define FLT_MIN .5397606e-78F                /* minimum float       */
#define DBL_MIN .53976053469340279e-78       /* minimum double      */
#define LDBL_MIN .53976053469340279e-78L     /* minimum long double */

Additionally, the header file <lcmath.h> declares useful mathematical constants, as listed in Constant Values Declared in lcmath.h.

Constant Values Declared in lcmath.h
Constant Representation
M_PI [pi]
M_PI_2 [pi]/2
M_PI_4 [pi]/4
M_1_PI 1/[pi]
M_2_PI 2/[pi]
M_E e
HUGE* largest possible double
TINY double closest to zero
LOGHUGE log(HUGE)
LOGTINY log(TINY)

In Constant Values Declared in lcmath.h, math.h defines the value HUGE_VAL , which is an ANSI-defined symbol with the same value.

The following are mathematical functions:
abs integer conversion: absolute value
acos compute the trigonometric arc cosine
asin compute the trigonometric arc sine
atan compute the trigonometric arc tangent
atan2 compute the trigonometric arc tangent of a quotient
ceil round up a floating-point number
cos compute the trigonometric cosine
cosh compute the hyperbolic cosine
div integer conversion: division
erf compute the error function
erfc compute the complementary error function
exp compute the exponential function
fabs floating-point conversion: absolute value
floor round down a floating-point number
fmax find the maximum of two doubles
fmin find the minimum of two doubles
fmod floating-point conversion: modules
frexp floating-point conversion: fraction-exponent split
gamma compute the logarithm of the gamma function
hypot compute the hypotenuse function
j0 Bessel function of the first kind, order 0
j1 Bessel function of the first kind, order 1
jn Bessel function of the first kind, order n
labs integer conversion: absolute value
llabs integer conversion: absolute value
ldexp floating-point conversion: load exponent
_ldexp fast implementation of ldexp
ldiv integer conversion: division
lldiv integer conversion: division
llmax find the maximum of two integers
llmin find the minimum of two integers
log compute the natural logarithm
log10 compute the common logarithm
_matherr handle math function error
max find the maximum of two integers
min find the minimum of two integers
modf floating-point conversion: fraction-integer split
pow compute the value of the power function
rand simple random number generation
sin compute the trigonometric sine
sinh compute the hyperbolic sine
sqrt compute the square root
srand simple random number generation
tan compute the trigonometric tangent
tanh compute the hyperbolic tangent
y0 Bessel function of the second kind, order 0
y1 Bessel function of the second kind, order 1
yn Bessel function of the second kind, order n.


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