GNU/Linux man pages
Livre :
Expressions régulières,
Syntaxe et mise en oeuvre :
GNU/Linux |
Debian 6.0.2(Squeeze) |
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erfl(3) |
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erf, erff, erfl, − error function
#include <math.h>
double
erf(double x);
float erff(float x);
long double erfl(long double x);
Link with −lm.
Feature Test Macro Requirements for glibc (see feature_test_macros(7)):
erf():
_BSD_SOURCE || _SVID_SOURCE ||
_XOPEN_SOURCE || _ISOC99_SOURCE ||
_POSIX_C_SOURCE >= 200112L;
or cc -std=c99
erff(), erfl():
_BSD_SOURCE || _SVID_SOURCE ||
_XOPEN_SOURCE >= 600 || _ISOC99_SOURCE ||
_POSIX_C_SOURCE >= 200112L;
or cc -std=c99
The
erf() function returns 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 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.
C99, POSIX.1-2001. The variant returning double also conforms to SVr4, 4.3BSD.
cerf(3), erfc(3), exp(3)
This page is part of release 3.27 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.
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erfl(3) | |