erfl(3) · carta

Usage

double erf(double x); float erff(float x); long double erfl(long double x);

_ISOC99_SOURCE { | | _POSIX_C_SOURCE >= 200112L | | _XOPEN_SOURCE}

_ISOC99_SOURCE { | | _POSIX_C_SOURCE >= 200112L}

Math library (libm, -lm)

These functions return the error function of x, defined as

erf(x) = 2/sqrt(pi) * integral from 0 to x of exp(-t*t) dt

On success, these functions return the value of the error function of x, a value in the range [-1, 1].

If x is a NaN, a NaN is returned.

If x is +0 (-0), +0 (-0) is returned.

If x is positive infinity (negative infinity), +1 (-1) is returned.

If x is subnormal, a range error occurs, and the return value is 2*x/sqrt(pi).

See math_error(7) for information on how to determine whether an error has occurred when calling these functions.

The following errors can occur:

Range error: result underflow (x is subnormal): An underflow floating-point exception (FE_UNDERFLOW) is raised.

These functions do not set errno.

For an explanation of the terms used in this section, see attributes(7).

Interface	Attribute	Value
erf(), erff(), erfl()	Thread safety	MT-Safe