GNU/Linux man pages
Livre :
Expressions régulières,
Syntaxe et mise en oeuvre :
GNU/Linux |
CentOS 5.6 |
|
 |
isinff(3) |
 |
finite, finitef, finitel, isinf, isinff, isinfl, isnan, isnanf, isnanl − BSD floating point classification functions
#define
_BSD_SOURCE
#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);
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.
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).
On a glibc system, these functions are declared by <math.h> when _BSD_SOURCE or _SVID_SOURCE or _GNU_SOURCE is defined. The isnan() functions will also be declared when _XOPEN_SOURCE is defined.
The finite() function occurs in 4.3BSD.
fpclassify(3), feature_test_macros(7)
|
isinff(3) | |