math(5)

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 double, float and long double-precision values.

It defines the structure and constants used by the matherr(3M) error-handling mechanisms, including the following constant used as an error-return value:

HUGE: The maximum value of a single-precision floating-point number.

The following mathematical constants are defined for user 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: , the ratio of the circumference of a circle to its diameter.
M_PI_2: /2.
M_PI_4: /4.
M_1_PI: 1/.
M_2_PI: 2/.
M_2_SQRTPI: 2/.
M_SQRT2: The positive square root of 2.
M_SQRT1_2: The positive square root of 1/2.

The numerical classification constants are defined in this header file:

FP_INFINITE
FP_NAN
FP_NORMAL
FP_SUBNORMAL
FP_ZERO: represent the mutually exclusive kinds of possible floating-point values. They expand to integer constant expressions with distinct values.

The following fma performance indicator constants are defined in this header file:

FP_FAST_FMA: If defined, FP_FAST_FMA indicates that fma(3M) generally executes about as fast as, or faster than a multiply and an add of double operands.
FP_FAST_FMAF: If defined, FP_FAST_FMF indicates that fmaf(3M) generally executes about as fast as, or faster than a multiply and an add of float operands.
FP_FAST_FMAL: If defined, FP_FAST_FMAL indicates that fmal(3M) generally executes about as fast as, or faster than a multiply and an add of long double operands.

NOTE: Typically, these constants are only defined if the fma functions are implemented directly with a hardware multiply-add instruction.

The following ilogb constants are defined in this header file:

FP_ILOGB0: Is set to either INT_MIN or -INT_MAX when ilogb(3M) is called with its argument set to zero.
FP_ILOGBNAN: Is set to either INT_MAX or INT_MIN when ilogb(3M) is called with its argument set to NaN.

The following integer constants used by math_errhandling are defined in this header file:

MATH_ERRNO: Expands to 1.
MATH_ERREXCEPT: Expands to 2.

The following mathematical constants are also defined in this header file:

MAXFLOAT: The maximum value of a non-infinite single-precision floating point number.
HUGE_VAL: A double constant expression representing positive infinity.
HUGE_VALF: A float constant expression representing positive infinity.
HUGE_VALL: A long double constant expression representing positive infinity.

The following constant is only defined on machines that support quiet NaNs for the float type:

NAN: A float constant expression representing a quiet NaN.

For the definitions of various machine-dependent constants, see values(5).

References

intro(3), matherr(3M), fma(3M), fmaf(3M), fmal(3M), ilogb(3M), values(5)