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
The general-purpose math library.
libm-sve
(QNX Neutrino 7.1 or later) A library that optimizes the code for ARMv8.2 chips that have Scalable Vector Extension hardware.

Your system requirements will determine how you should work with these libraries:

• If you want only selected processes to run with the SVE version, you can include both libraries in your OS image and use the -l m or -l m-sve option to qcc to link explicitly against the appropriate one.
• If you want all processes to use the SVE version, include libm-sve.so in your OS image and set up a symbolic link from libm.so to libm-sve.so. Use the -l m option to qcc to link against the library.
Note: Compile your program with the -fno-builtin option to prevent the compiler from using a built-in version of the function.

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:

Safety:
Cancellation point No
Interrupt handler Yes
Signal handler Yes