isnan(3) [redhat man page]

ISINF(3)						     Linux Programmer's Manual							  ISINF(3)

NAME

       isinf, isnan, finite - test for infinity or not-a-number (NaN)

SYNOPSIS

       #include <math.h>

       int isinf(double value);

       int isnan(double value);

       int finite(double value);

DESCRIPTION

       The isinf() function returns -1 if value represents negative infinity, 1 if value represents positive infinity, and 0 otherwise.

       The isnan() function returns a non-zero value if value is "not-a-number" (NaN), and 0 otherwise.

       The finite() function returns a non-zero value if value is neither infinite nor a "not-a-number" (NaN) value, and 0 otherwise.

CONFORMING TO

       BSD 4.3

GNU
								    1993-06-02								  ISINF(3)

FINITE(3)						     Linux Programmer's Manual							 FINITE(3)

NAME

       finite, finitef, finitel, isinf, isinff, isinfl, isnan, isnanf, isnanl - BSD floating-point classification functions

SYNOPSIS

       #include <math.h>

       int finite(double x);
       int finitef(float x);
       int finitel(long double x);

       int isinf(double x);
       int isinff(float x);
       int isinfl(long double x);

       int isnan(double x);
       int isnanf(float x);
       int isnanl(long double x);

   Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

       finite(), finitef(), finitel():
	   _BSD_SOURCE || _SVID_SOURCE
       isinf():
	   _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600 || _ISOC99_SOURCE;
	   or cc -std=c99
       isinff(), isinfl():
	   _BSD_SOURCE || _SVID_SOURCE
       isnan():
	   _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE || _ISOC99_SOURCE;
	   or cc -std=c99
       isnanf(), isnanl():
	   _BSD_SOURCE || _SVID_SOURCE || _XOPEN_SOURCE >= 600

DESCRIPTION

       The finite() functions return a nonzero value if x is neither infinite nor a "not-a-number" (NaN) value, and 0 otherwise.

       The isnan() functions return a nonzero value if x is a NaN value, and 0 otherwise.

       The isinf() functions return 1 if x is positive infinity, -1 if x is negative infinity, and 0 otherwise.

NOTES

       Note  that these functions are obsolete.  C99 defines macros isfinite(), isinf(), and isnan() (for all types) replacing them.  Further note
       that the C99 isinf() has weaker guarantees on the return value.	See fpclassify(3).

SEE ALSO

       fpclassify(3)

COLOPHON

       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/.

								    2008-08-05								 FINITE(3)