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NAME | SYNOPSIS | DESCRIPTION | ATTRIBUTES | NOTES | SEE ALSO | COLOPHON |
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FINITE(3) Linux Programmer's Manual FINITE(3)
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
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
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.
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() │ │ │
└────────────────────────────────┴───────────────┴─────────┘
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).
fpclassify(3)
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)
Pages that refer to this page: fpclassify(3)
Copyright and license for this manual page
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