erf(), erff(), erfl()

Compute the error function of a number

Synopsis:

#include <math.h>

double erf ( double x );

float erff ( float x );

long double erfl ( long double x );

Arguments:

x
The number for which you want to compute the error function.

Library:

libm

Use the -l m option to qcc to link against this library.

Description:

The erf(), erff(), and erfl() functions compute the following:

If x is large and the result of erf() is subtracted from 1.0, the results aren't very accurate; use erfc() instead.

This equality is true: erf(-x) = -erf(x)

To check for error situations, use feclearexcept() and fetestexcept():

Returns:

The value of the error function. If the correct value would cause underflow, a range error occurs, and erf(), erff(), and erfl() return DBL_MIN, FLT_MIN, and LDBL_MIN, respectively.

If x is: These functions return:
NaN NaN
±0 ±0
±Inf ±1

Errors:

FE_UNDERFLOW
The result would cause an underflow.

Classification:

ANSI, POSIX 1003.1

Safety:  
Cancellation point No
Interrupt handler No
Signal handler No
Thread Yes