Miscellaneous Functions

Intel® C++ Compiler Classic Developer Guide and Reference

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Date 12/16/2022

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Miscellaneous Functions

Many routines in the Intel® C++ Compiler Classic Math Library are more optimized for Intel® microprocessors than for non-Intel microprocessors.

The mathimf.h header file includes prototypes for Intel® C++ Compiler Classic Math Library functions.

The math library supports the following miscellaneous functions:

copysign

Description: The copysign function returns the value with the magnitude of x and the sign of y.

Calling interface:
double copysign(double x, double y);
long double copysignl(long double x, long double y);
float copysignf(float x, float y);

fabs

Description: The fabs function returns the absolute value of x.

Calling interface:
double fabs(double x);
long double fabsl(long double x);
float fabsf(float x);

fdim

Description: The fdim function returns the positive difference value, x-y (for x > y) or +0 (for x <= to y).

errno: ERANGE, for overflow conditions

Calling interface:
double fdim(double x, double y);
long double fdiml(long double x, long double y);
float fdimf(float x, float y);

finite

Description: The finite function returns 1 if x is not a NaN or +/- infinity. Otherwise 0 is returned.

Calling interface:
int finite(double x);
int finitel(long double x);
int finitef(float x);

fma

Description: The fma functions return (x*y)+z.

Calling interface:
double fma(double x, double y, double z);
long double fmal(long double x, long double y, long double z);
float fmaf(float x, float y, float z);

fmax

Description: The fmax function returns the maximum numeric value of its arguments.

Calling interface:
double fmax(double x, double y);
long double fmaxl(long double x, long double y);
float fmaxf(float x, float y);

fmin

Description: The fmin function returns the minimum numeric value of its arguments.

Calling interface:
double fmin(double x, double y);
long double fminl(long double x, long double y);
float fminf(float x, float y);

fpclassify

Description: The fpclassify function returns the value of the number classification macro appropriate to the value of its argument.

Return Value
0 (NaN)
1 (Infinity)
2 (Zero)
3 (Subnormal)
4 (Finite)

Calling interface:
int fpclassify(double x);
int fpclassifyl(long double x);
int fpclassifyf(float x);

isfinite

Description: The isfinite function returns 1 if x is not a NaN or +/- infinity. Otherwise 0 is returned.

Calling interface:
int isfinite(double x);
int isfinitel(long double x);
int isfinitef(float x);

isgreater

Description: The isgreater function returns 1 if x is greater than y. This function does not raise the invalid floating-point exception.

Calling interface:
int isgreater(double x, double y);
int isgreaterl(long double x, long double y);
int isgreaterf(float x, float y);

isgreaterequal

Description: The isgreaterequal function returns 1 if x is greater than or equal to y. This function does not raise the invalid floating-point exception.

Calling interface:
int isgreaterequal(double x, double y);
int isgreaterequall(long double x, long double y);
int isgreaterequalf(float x, float y);

isinf

Description: The isinf function returns a non-zero value if and only if its argument has an infinite value.

Calling interface:
int isinf(double x);
int isinfl(long double x);
int isinff(float x);

isless

Description: The isless function returns 1 if x is less than y. This function does not raise the invalid floating-point exception.

Calling interface:
int isless(double x, double y);
int islessl(long double x, long double y);
int islessf(float x, float y);

islessequal

Description: The islessequal function returns 1 if x is less than or equal to y. This function does not raise the invalid floating-point exception.

Calling interface:
int islessequal(double x, double y);
int islessequall(long double x, long double y);
int islessequalf(float x, float y);

islessgreater

Description: The islessgreater function returns 1 if x is less than or greater than y. This function does not raise the invalid floating-point exception.

Calling interface:
int islessgreater(double x, double y);
int islessgreaterl(long double x, long double y);
int islessgreaterf(float x, float y);

isnan

Description: The isnan function returns a non-zero value, if and only if x has a NaN value.

Calling interface:
int isnan(double x);
int isnanl(long double x);
int isnanf(float x);

isnormal

Description: The isnormal function returns a non-zero value, if and only if x is normal.

Calling interface:
int isnormal(double x);
int isnormall(long double x);
int isnormalf(float x);

isunordered

Description: The isunordered function returns 1 if either x or y is a NaN. This function does not raise the invalid floating-point exception.

Calling interface:
int isunordered(double x, double y);
int isunorderedl(long double x, long double y);
int isunorderedf(float x, float y);

maxmag

Description: The maxmag function returns the value of larger magnitude from among its two arguments, x and y. If |x| > |y| it returns x; if |y| > |x| it returns y; otherwise it behaves like fmax(x,y).

Calling interface:
double maxmag(double x, double y);
float maxmagf(float x, float y);

minmag

Description: The minmag function returns the value of smaller magnitude from among its two arguments, x and y. If |x| < |y| it returns x; if |y| < |x| it returns y; otherwise it behaves like fmin(x,y).

Calling interface:
double minmag(double x, double y);
float minmagf(float x, float y);

nan

Description: The nan function returns a quiet NaN, with content indicated through tagp.

Calling interface:
double nan(const char *tagp);
long double nanl(const char *tagp);
float nanf(const char *tagp);

nextafter

Description: The nextafter function returns the next representable value in the specified format after x in the direction of y.

errno: ERANGE, for overflow and underflow conditions

Calling interface:
double nextafter(double x, double y);
long double nextafterl(long double x, long double y);
float nextafterf(float x, float y);

nexttoward

Description: The nexttoward function returns the next representable value in the specified format after x in the direction of y. If x equals y, then the function returns y converted to the type of the function. Use the Qlong-double option (for C++ only) on Windows* operating systems for accurate results.

errno: ERANGE, for overflow and underflow conditions

Calling interface:
double nexttoward(double x, long double y);
long double nexttowardl(long double x, long double y);
float nexttowardf(float x, long double y);

signbit

Description: The signbit function returns a non-zero value, if and only if the sign of x is negative.

Calling interface:
int signbit(double x);
int signbitl(long double x);
int signbitf(float x);

significand

Description: The significand function returns the significand of x in the interval [1,2). For x equal to zero, NaN, or +/- infinity, the original x is returned.

Calling interface:
double significand(double x);
long double significandl(long double x);
float significandf(float x);

Parent topic: Intel® C++ Compiler Classic Math Library

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Intel® C++ Compiler Classic Developer Guide and Reference

Miscellaneous Functions

copysign

fabs

fdim

finite

fma

fmax

fmin

fpclassify

isfinite

isgreater

isgreaterequal

isinf

isless

islessequal

islessgreater

isnan

isnormal

isunordered

maxmag

minmag

nan

nextafter

nexttoward

signbit

significand