функции классификации с плавающей запятой BSD (BSD floating-point classification functions)
Имя (Name)
finite, finitef, finitel, isinf, isinff, isinfl, isnan, isnanf,
isnanl - BSD floating-point classification functions
Синопсис (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():
/* Glibc since 2.19: */ _DEFAULT_SOURCE
|| /* Glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
isinf():
_XOPEN_SOURCE >= 600 || _ISOC99_SOURCE
|| /* Glibc since 2.19: */ _DEFAULT_SOURCE
|| /* Glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
isinff(), isinfl():
/* Glibc since 2.19: */ _DEFAULT_SOURCE
|| /* Glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
isnan():
_XOPEN_SOURCE || _ISOC99_SOURCE
|| /* Glibc since 2.19: */ _DEFAULT_SOURCE
|| /* Glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
isnanf(), isnanl():
_XOPEN_SOURCE >= 600
|| /* Glibc since 2.19: */ _DEFAULT_SOURCE
|| /* Glibc <= 2.19: */ _BSD_SOURCE || _SVID_SOURCE
Описание (Description)
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.
Атрибуты (Attributes)
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() │ │ │
└──────────────────────────────────────┴───────────────┴─────────┘
Примечание (Note)
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).
Смотри также (See also)
fpclassify(3)
