23rd June 2020, 1 min read

Calling C from Julia

Two ways to compute the error function or Bessel function in Julia.

1. Calling C. On UNIX libm provides erf() and j0(). So calling them goes like this:

ccall(("erf","libm.so.6"),Float64,(Float64,),0.1)
ccall(("j0"),Float64,(Float64,),3)

In this case one can omit the reference to libm.so. Watch out for the funny looking (Float64,).

2. Using Julia. SpecialFunctions.jl provides erf() and besselj0.

import Pkg
Pkg.add("SpecialFunctions")
import SpecialFunctions
SpecialFunctions.erf(0.1)
SpecialFunctions.besselj0(3)