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():
           /* Glibc since 2.19: */ _DEFAULT_SOURCE
               || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
       isinf():
           _XOPEN_SOURCE >= 600 || _ISOC99_SOURCE
               || /* Glibc since 2.19: */ _DEFAULT_SOURCE
               || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
       isinff(), isinfl():
           /* Glibc since 2.19: */ _DEFAULT_SOURCE
               || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
       isnan():
           _XOPEN_SOURCE || _ISOC99_SOURCE
               || /* Glibc since 2.19: */ _DEFAULT_SOURCE
               || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
       isnanf(), isnanl():
           _XOPEN_SOURCE >= 600
               || /* Glibc since 2.19: */ _DEFAULT_SOURCE
               || /* Glibc versions <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE

DESCRIPTION

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

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

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

ATTRIBUTES

       For an explanation of the terms used in this section, see attributes(7).

       ┌────────────────────────────────┬───────────────┬─────────┐
       │Interface                       │ Attribute     │ Value   │
       ├────────────────────────────────┼───────────────┼─────────┤
       │finite(), finitef(), finitel(), │ Thread safety │ MT-Safe │
       │isinf(), isinff(), isinfl(),    │               │         │
       │isnan(), isnanf(), isnanl()     │               │         │
       └────────────────────────────────┴───────────────┴─────────┘

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 4.15 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/.

                                            2017-09-15                                  FINITE(3)