auto wrapper

src/gen/gsl_types.jl

@@ -876,7 +876,7 @@ defined in `gsl_math.h`.
 """
 mutable struct gsl_function
     function_::Ptr{Cvoid}
-    params::Ptr{Cvoid}
+    params
 end
 
 @doc md"""

src/manual_wrappers.jl

@@ -30,6 +30,25 @@ end
 
 
 ## Root finding
+
+# wrapper function
+function gsl_function_helper(x::Cdouble, @nospecialize(fn::Any))::Cdouble
+    try
+        return Cdouble(fn(x))
+    catch
+        return NaN
+    end
+end
+
+function Base.cconvert(::Type{Ref{gsl_function}}, fn)
+    fptr = @cfunction(gsl_function_helper, Cdouble, (Cdouble, Any))
+    convert(Ref{gsl_function}, gsl_function(fptr, fn))
+end
+
+Base.cconvert(::Type{Ref{gsl_function}}, gslf::gsl_function) = 
+    convert(Ref{gsl_function}, gslf)
+
+
 # Macros for easier creation of gsl_function and gsl_function_fdf structs
 export @gsl_function, @gsl_function_fdf
 

test/numdiff.jl

@@ -12,7 +12,7 @@ func(x) = x^3
 
     for deriv in [deriv_central, deriv_forward, deriv_backward]
         df,ddf = Cdouble[0], Cdouble[0]
-        deriv(@gsl_function(func), x, h, df, ddf)
+        deriv(func, x, h, df, ddf)
         @test abs(df_dx - df[]) <= ddf[] <= d2f_dx2*h/2 + 2eps()/h
     end
 end

test/quadrature.jl

@@ -3,17 +3,16 @@ using GSL
 
 fquad = x -> x^1.5
 @testset "Quadrature" begin
+    fquad = x -> x^1.5
     ws_size = 100
     ws = integration_cquad_workspace_alloc(ws_size)
 
-    ff = @gsl_function(fquad)
-
     a = 0
     b = 1
     result = Cdouble[0]
     abserr = Cdouble[0]
     nevals = Csize_t[0]
-    integration_cquad(ff, a, b, 1e-10, 1e-10, ws, result, abserr, nevals)
+    integration_cquad(fquad, a, b, 1e-10, 1e-10, ws, result, abserr, nevals)
 
     @test abs(result[] - 1/2.5) < abserr[]