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jn(), jnf()

Compute a Bessel function of the first kind


#include <math.h>

double jn( int n, double x );

float jnf( int n, float x );


n, x
The numbers that you want to compute the Bessel function for.



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


Compute the Bessel function of the first kind for n and x.


The result of the Bessel function of n and x.

Note: If an error occurs, these functions return 0, but this is also a valid mathematical result. If you want to check for errors, set errno to 0, call the function, and then check errno again. These functions don't change errno if no errors occurred.


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

int main( void )
    double x, y, z;

    x = j0( 2.4 );
    y = y1( 1.58 );
    z = jn( 3, 2.4 );

    printf( "j0(2.4) = %f, y1(1.58) = %f\n", x, y );
    printf( "jn(3,2.4) = %f\n", z );

    return EXIT_SUCCESS;


jn() is POSIX 1003.1 XSI; jnf() is Unix

Cancellation point No
Interrupt handler No
Signal handler No
Thread Yes

See also:

errno, j0(), j1(), y0(), y1(), yn()