2 Copyright 1988-2022 Free Software Foundation, Inc.
3 This is part of the GCC manual.
4 For copying conditions, see the copyright.rst file.
14 .. index:: Bessel function, first kind
16 BESSEL_J0 --- Bessel function of the first kind of order 0
17 **********************************************************
19 .. function:: BESSEL_J0(X)
21 ``BESSEL_J0(X)`` computes the Bessel function of the first kind of
22 order 0 of :samp:`{X}`. This function is available under the name
23 ``BESJ0`` as a GNU extension.
26 The type shall be ``REAL``.
29 The return value is of type ``REAL`` and lies in the
30 range - 0.4027... \leq Bessel (0,x) \leq 1. It has the same
34 Fortran 2008 and later
40 .. code-block:: fortran
45 .. code-block:: fortran
50 end program test_besj0