infnan(3) — Linux manual pages

Linux manual pages	Section 3

Name

infnan — deal with infinite or not-a-number (NaN) result

Synopsis

#include <math.h>

double infnan( int error);

	Note
	Link with `−lm`.

DESCRIPTION

The infnan() function returns a suitable value for infinity and "not-a-number" (NaN) results. The value of error can be ERANGE to represent infinity or anything else to represent NaN. errno is also set.

RETURN VALUE

If error is ERANGE (Infinity), HUGE_VAL is returned.

If error is −ERANGE (−Infinity), −HUGE_VAL is returned.

If error is anything else, NAN is returned.

ERRORS

EDOM: The value of error is "not-a-number" (NaN).
ERANGE: The value of error is positive infinity or negative infinity.

CONFORMING TO

4.3BSD.

NOTES

This obsolete function was provided in libc4 and libc5, but is not available in glibc2.

COLOPHON

This page is part of release 4.07 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at https://www.kernel.org/doc/man−pages/.

  Copyright 1993 David Metcalfe (davidprism.demon.co.uk)

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References consulted:
    Linux libc source code
    Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991)
    386BSD man pages
Modified Sat Jul 24 19:11:11 1993 by Rik Faith (faithcs.unc.edu)
Modified 2004-11-12 as per suggestion by Fabian Kreutz/AEB
to note that this function is not available in glibc2.