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


   #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
       _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
           || /* 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


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

   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.


   For  an  explanation  of  the  terms  used   in   this   section,   see

   │InterfaceAttributeValue   │
   │finite(), finitef(), finitel(), │ Thread safety │ MT-Safe │
   │isinf(), isinff(), isinfl(),    │               │         │
   │isnan(), isnanf(), isnanl()     │               │         │


   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




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                              2016-03-15                         FINITE(3)


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