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NAME | LIBRARY | SYNOPSIS | DESCRIPTION | ATTRIBUTES | NOTES | SEE ALSO | COLOPHON |
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finite(3) Library Functions Manual finite(3)
finite, finitef, finitel, isinf, isinff, isinfl, isnan, isnanf,
isnanl - BSD floating-point classification functions
Math library (libm, -lm)
#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 >= 2.19: */ _DEFAULT_SOURCE
|| /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
isinf():
_XOPEN_SOURCE >= 600 || _ISOC99_SOURCE
|| /* glibc >= 2.19: */ _DEFAULT_SOURCE
|| /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
isinff(), isinfl():
/* glibc >= 2.19: */ _DEFAULT_SOURCE
|| /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
isnan():
_XOPEN_SOURCE || _ISOC99_SOURCE
|| /* glibc >= 2.19: */ _DEFAULT_SOURCE
|| /* glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
isnanf(), isnanl():
_XOPEN_SOURCE >= 600
|| /* glibc >= 2.19: */ _DEFAULT_SOURCE
|| /* glibc <= 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 the man-pages (Linux kernel and C library
user-space interface documentation) project. Information about
the project can be found at
⟨https://www.kernel.org/doc/man-pages/⟩. If you have a bug report
for this manual page, see
⟨https://git.kernel.org/pub/scm/docs/man-pages/man-pages.git/tree/CONTRIBUTING⟩.
This page was obtained from the tarball man-pages-6.9.1.tar.gz
fetched from
⟨https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/⟩ on
2024-06-26. If you discover any rendering problems in this HTML
version of the page, or you believe there is a better or more up-
to-date source for the page, or you have corrections or
improvements to the information in this COLOPHON (which is not
part of the original manual page), send a mail to
man-pages@man7.org
Linux man-pages 6.9.1 2024-05-02 finite(3)
Pages that refer to this page: fpclassify(3)
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HTML rendering created 2024-06-26 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
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