itrunc(3) Library Functions Manual itrunc(3)NAME
itrunc, uitrunc - Truncate a floating-point number
LIBRARY
Standard C Library (libc.a)
SYNOPSIS
#include <math.h>
int itrunc(
double x); unsigned int uitrunc(
double x);
DESCRIPTION
The itrunc function returns the signed integer nearest to the double-precision floating value x in the direction of 0.0. This effectively
truncates x by discarding its fraction component. The uitrunc function also truncates the double x, but returns an unsigned integer
value.
If x is a NaN or a negative value that exceeds the size of a signed integer, itrunc returns INT_MIN. If x is a positive value that exceeds
the size of a signed integer, itrunc returns INT_MAX.
If x is a NaN or a negative value that exceeds the size of an unsigned integer, uitrunc returns a zero. If x is a positive value that
exceeds the size of an unsigned integer, itrunc returns UINT_MAX.
RELATED INFORMATION
Files: float.h, fp.h, limits.h, machine/fpu.h, math.h,
IEEE Standard for Binary Floating-Point Arithmetic delim off
itrunc(3)
Check Out this Related Man Page
ieee_functions(3) Library Functions Manual ieee_functions(3)NAME
copysign, finite, fp_class, isnan, nextafter, unordered - Related miscellaneous IEEE arithmetic functions.
LIBRARY
Math Library (libm.a)
SYNOPSIS
#include <math.h>
double copysign (double x, double y); float copysignf (float x, float y); long double copysignl (long double x, long double y); int
finite (double x); int finitef (float x); int finitel (long double x); int fp_class (double x); int fp_classf
(float x); int fp_classl (long double x); int isnan (double x); int isnanf (float x); int isnanl (long double
x); double nextafter (double x, double y); float nextafterf (float x, float y); long double nextafterl (long double x, long double y);
int unordered (double x, double y); int unorderedf (float x, float y); int unorderedl (long double x, long double y);
STANDARDS
Interfaces documented on this reference page conform to industry standards as follows:
isnan(): XPG4
nextafter(): XPG4-UNIX
Refer to the standards(5) reference page for more information about industry standards and associated tags.
DESCRIPTION
The copysign(), copysignf(), and copysignl() functions return x with the same sign as y. IEEE 754 requires copysign(x,NaN), copy-
signf(x,NaN) and copysignl(x,NaN) to return +x or -x.
The finite(), finitef(), and finitel() functions return the integer value 1 (True) or 0 (False). The finite(x), finitef(x),
and finitel(x) functions return 1 when -infinity < x < +infinity. They return 0 when |x| = infinity or x is a NaN.
The fp_class(), fp_classf(), and fp_classl() functions determine the class of an IEEE floating-point value. They return one of the con-
stants in the file <fp_class.h> and never cause an exception, even for signaling NaNs. These routines implement the recommended function
class(x) in the appendix of the IEEE 754-1985 standard for binary floating-point arithmetic. The constants in <fp_class.h> refer to the
following classes of values:
-----------------------------------------------------
Constant Class
-----------------------------------------------------
FP_SNAN Signaling NaN (Not-a-Number)
FP_QNAN Quiet NaN (Not-a-Number)
FP_POS_INF +infinity
FP_NEG_INF -infinity
FP_POS_NORM Positive normalized
FP_NEG_NORM Negative normalized
FP_POS_DENORM Positive denormalized
FP_NEG_DENORM Negative denormalized
FP_POS_ZERO +0.0 (positive zero)
FP_NEG_ZERO -0.0 (negative zero)
-----------------------------------------------------
The isnan(), isnanf(), and isnanl() functions return the value 1 (True) if x is NaN (the IEEE floating point reserved not-a-number value);
otherwise, it returns the value 0 (False).
The nextafter(), nextafterf(), and nextafterl() functions return the next machine-representable number from x in the direction of y.
The unordered(), unorderedf(), and unorderedl() functions return the value 1 (True) if either x or y or both is a NaN; otherwise, it
returns the value 0 (False).
RELATED INFORMATION drem(3), logb(3), scalb(3), rint(3), sqrt(3), and ANSI/IEEE Std 754-1985, IEEE Standard for Binary Floating-Point Arithmetic delim off
ieee_functions(3)