hypot(), hypotf(), hypotl()

Calculate the length of the hypotenuse for a right-angled triangle

Synopsis:

#include <math.h>

double hypot( double x, 
              double y );

float hypotf( float x, 
              float y );

long double hypotl( long double x, 
                    long double y );

Arguments:

x, y: The lengths of the sides that are adjacent to the right angle.

Library:

libm

Use the -l m option to qcc to link against this library.

Description:

These functions compute the length of the hypotenuse for a right triangle whose sides are x and y adjacent to the right angle. The calculation is equivalent to:

length = sqrt( x*x + y*y );

To check for error situations, use feclearexcept() and fetestexcept(). For example:

Call feclearexcept(FE_ALL_EXCEPT) before calling hypot(), hypotf(), or hypotl().
On return, if fetestexcept(FE_ALL_EXCEPT) is nonzero, then an error has occurred.

Returns:

The length of the hypotenuse.

If:	These functions return:	Errors:
The correct value would cause overflow	Inf	FE_OVERFLOW
`x` or `y` is ±Inf, and the other is any value including NaN	Inf	—
`x` or `y` is NaN, and the other isn't ±Inf	NaN	—
The correct result would cause underflow	The correct result, after rounding	FE_UNDERFLOW

These functions raise FE_INEXACT if the FPU reports that the result can't be exactly represented as a floating-point number.

Examples:

#include <stdio.h>
#include <math.h>
#include <fenv.h>
#include <stdlib.h>

int main( void )
{
    int except_flags;

    feclearexcept(FE_ALL_EXCEPT);

    printf( "%f\n", hypot( 3.0, 4.0 ) );

    except_flags = fetestexcept(FE_ALL_EXCEPT);
    if(except_flags) {
        /* An error occurred; handle it appropriately. */
    }

    return EXIT_SUCCESS;
}

produces the output:

5.000000

Classification:

ANSI, POSIX 1003.1

Safety:
Cancellation point	No
Interrupt handler	No
Signal handler	No
Thread	Yes