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finite (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(), isinff(), isinfl(): _BSD_SOURCE || _SVID_SOURCE
isnan(), isnanf(), isnanl(): _BSD_SOURCE || _SVID_SOURCE ||
_XOPEN_SOURCE
DESCRIPTION
The finite() functions return a non-zero value if x is neither infinite
nor a "not-a-number" (NaN) value, and 0 otherwise.
The isnan() functions return a non-zero value if x is a NaN value, and
0 otherwise.
The isinf() functions return 1 if x is plus infinity, -1 is x is minus
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 fpclas-
sify(3).
SEE ALSO
fpclassify(3)
2007-07-26 FINITE(3)
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