*Compute the error function of a number*

#include <math.h> double erf ( doublex); float erff ( floatx);

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

`libm`

Use the ` -l m` option to

The *erf()* and *erff()*
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*)

The value of the error function, or NAN
if *x* is NAN.

If an error occurs, these functions return 0, but this is also a valid
mathematical result.
If you want to check for errors, set
errno
to 0, call the function, and then check errno again.
These functions don't change errno if no errors occurred. |

Safety: | |
---|---|

Cancellation point | No |

Interrupt handler | No |

Signal handler | No |

Thread | Yes |