ERFC(3) | Library Functions Manual | ERFC(3)

# NAME

`erf`, `erff`, `erfl`, `erfc`, `erfcf`, `erfcl` — error function operators

# SYNOPSIS

Math Library (libm, -lm)
`#include <math.h>`

double
`erf`(double x);

float
`erff`(float x);

long double
`erfl`(long double x);

double
`erfc`(double x);

float
`erfcf`(float x);

long double
`erfcl`(long double x);

# DESCRIPTION

These functions calculate the error function of x.

The `erf`() function calculates the error function of x, and the `erff`() and `erfl`() functions are single and double precision versions of `erf`(). The error function is defined as:

    erfx=2π∫0xe−t2dt

The `erfc`() function calculates the complementary error function of x; that is `erfc`() subtracts the result of the error function `erf`(x) from 1.0. This is useful, since for large x places disappear. The `erfcf`() and `erfcl`() functions are single and double precision version of `erfc`().

# SEE ALSO

exp(3)

# HISTORY

The `erf`() and `erfc`() functions first appeared in Version 7 AT&T UNIX/32V.

June 7, 2025 | Debian