NAME
finite, finitef, finitel, isinf, isinff, isinfl, isnan, isnanf, isnanl - BSD floating-point classification functions
LIBRARY
Math library (libm, -lm)
SYNOPSIS
#include <math.h>int finite(double \nx\n);\n
\nint finitef(float \nx\n);\n
\nint finitel(long double \nx\n);int isinf(double \nx\n);\n
\nint isinff(float \nx\n);\n
\nint isinfl(long double \nx\n);int isnan(double \nx\n);\n
\nint isnanf(float \nx\n);\n
\nint isnanl(long double \nx\n);finite(), finitef(), finitel():
\n
/* glibc >= 2.19: */ _DEFAULT_SOURCE
\n
|| /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCEisinf\n():
\n
_XOPEN_SOURCE >= 600 || _ISOC99_SOURCE
\n
|| /* glibc >= 2.19: */ _DEFAULT_SOURCE
\n
|| /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCEisinff(), isinfl():
\n
/* glibc >= 2.19: */ _DEFAULT_SOURCE
\n
|| /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCEisnan():
\n
_XOPEN_SOURCE || _ISOC99_SOURCE
\n
|| /* glibc >= 2.19: */ _DEFAULT_SOURCE
\n
|| /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCEisnanf(), isnanl():
\n
_XOPEN_SOURCE >= 600
\n
|| /* glibc >= 2.19: */ _DEFAULT_SOURCE
\n
|| /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCEDESCRIPTION
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 (), isinf (), isinff (), isinfl (), isnan (), isnanf (), isnanl () | Thread safety | MT-Safe |
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)