Proper handling of some callbacks and create some wrapper objects with automatic memory management

Project.toml

@@ -6,10 +6,12 @@ version = "1.0.1"
 Libdl = "8f399da3-3557-5675-b5ff-fb832c97cbdb"
 GSL_jll = "1b77fbbe-d8ee-58f0-85f9-836ddc23a7a4"
 Markdown = "d6f4376e-aef5-505a-96c1-9c027394607a"
+REPL = "3fa0cd96-eef1-5676-8a61-b3b8758bbffb"
 
 [compat]
 SpecialFunctions = "0.8, 0.9, 0.10, 1"
 GSL_jll = "2.6"
+REPL = "1.3.0"
 julia = "1.3.0"
 
 [extras]

README.md

@@ -72,9 +72,8 @@ GSL.C.sf_legendre_array(GSL_SF_LEGENDRE_SPHARM, lmax, x, result)
 ```julia
 f = x -> x^5+1
 df = x -> 5*x^4
-fdf = @gsl_function_fdf(f, df)
-solver = root_fdfsolver_alloc(gsl_root_fdfsolver_newton)
-root_fdfsolver_set(solver, fdf, -2)
+solver = GSLRootFDFSolver(gsl_root_fdfsolver_newton)
+root_fdfsolver_set(solver, (f, df), -2)
 while abs(f(root_fdfsolver_root(solver))) > 1e-10
     root_fdfsolver_iterate(solver)
 end
@@ -87,7 +86,6 @@ println("x = ", root_fdfsolver_root(solver))
 Extra functionality defined in this package:
 
 * Convenience functions `hypergeom` and `hypergeom_e` for the hypergeometric functions.
-* Function wrapping macros `@gsl_function`, `@gsl_function_fdf`, `@gsl_multiroot_function` and `@gsl_multiroot_function_fdf` that are used for packaging Julia functions so that they can be passed to GSL.
 * Functions `wrap_gsl_vector` and `wrap_gsl_matrix` that return a Julia array or matrix pointing to the data in a `gsl_vector` or `gsl_matrix`.
 
 In addition, some effort has been put into giving most types and functions proper docstrings, e.g.

src/GSL.jl

@@ -1,6 +1,7 @@
 module GSL
 
 using Markdown
+using REPL # For Docs.doc
 
 # BEGIN MODULE C
 # low-level interface

src/gen/direct_wrappers/gsl_chebyshev_h.jl

@@ -57,7 +57,7 @@ GSL documentation:
 > and requires $n$ function evaluations.
 
 """
-function cheb_init(cs, func, a, b)
+function cheb_init(cs, func::gsl_function, a, b)
     ccall((:gsl_cheb_init, libgsl), Cint, (Ref{gsl_cheb_series}, Ref{gsl_function}, Cdouble, Cdouble), cs, func, a, b)
 end
 

src/gen/direct_wrappers/gsl_deriv_h.jl

@@ -32,7 +32,7 @@ GSL documentation:
 > actually used.
 
 """
-function deriv_central(f, x, h, result, abserr)
+function deriv_central(f::F, x, h, result, abserr) where F
     ccall((:gsl_deriv_central, libgsl), Cint, (Ref{gsl_function}, Cdouble, Cdouble, Ref{Cdouble}, Ref{Cdouble}), f, x, h, result, abserr)
 end
 
@@ -58,7 +58,7 @@ GSL documentation:
 > negative step-size.
 
 """
-function deriv_backward(f, x, h, result, abserr)
+function deriv_backward(f::F, x, h, result, abserr) where F
     ccall((:gsl_deriv_backward, libgsl), Cint, (Ref{gsl_function}, Cdouble, Cdouble, Ref{Cdouble}, Ref{Cdouble}), f, x, h, result, abserr)
 end
 
@@ -89,7 +89,7 @@ GSL documentation:
 > $x+h/2$, $x+h$.
 
 """
-function deriv_forward(f, x, h, result, abserr)
+function deriv_forward(f::F, x, h, result, abserr) where F
     ccall((:gsl_deriv_forward, libgsl), Cint, (Ref{gsl_function}, Cdouble, Cdouble, Ref{Cdouble}, Ref{Cdouble}), f, x, h, result, abserr)
 end
 

src/gen/direct_wrappers/gsl_diff_h.jl

@@ -12,7 +12,7 @@
 C signature:
 `int gsl_diff_central (const gsl_function *f, double x, double *result, double *abserr)`
 """
-function diff_central(f, x, result, abserr)
+function diff_central(f::F, x, result, abserr) where F
     ccall((:gsl_diff_central, libgsl), Cint, (Ref{gsl_function}, Cdouble, Ref{Cdouble}, Ref{Cdouble}), f, x, result, abserr)
 end
 
@@ -22,7 +22,7 @@ end
 C signature:
 `int gsl_diff_backward (const gsl_function *f, double x, double *result, double *abserr)`
 """
-function diff_backward(f, x, result, abserr)
+function diff_backward(f::F, x, result, abserr) where F
     ccall((:gsl_diff_backward, libgsl), Cint, (Ref{gsl_function}, Cdouble, Ref{Cdouble}, Ref{Cdouble}), f, x, result, abserr)
 end
 
@@ -32,7 +32,7 @@ end
 C signature:
 `int gsl_diff_forward (const gsl_function *f, double x, double *result, double *abserr)`
 """
-function diff_forward(f, x, result, abserr)
+function diff_forward(f::F, x, result, abserr) where F
     ccall((:gsl_diff_forward, libgsl), Cint, (Ref{gsl_function}, Cdouble, Ref{Cdouble}, Ref{Cdouble}), f, x, result, abserr)
 end
 

src/gen/direct_wrappers/gsl_integration_h.jl

@@ -253,7 +253,7 @@ end
 C signature:
 `void gsl_integration_qk15 (const gsl_function * f, double a, double b, double *result, double *abserr, double *resabs, double *resasc)`
 """
-function integration_qk15(f, a, b, result, abserr, resabs, resasc)
+function integration_qk15(f::F, a, b, result, abserr, resabs, resasc) where F
     ccall((:gsl_integration_qk15, libgsl), Cvoid, (Ref{gsl_function}, Cdouble, Cdouble, Ref{Cdouble}, Ref{Cdouble}, Ref{Cdouble}, Ref{Cdouble}), f, a, b, result, abserr, resabs, resasc)
 end
 
@@ -263,7 +263,7 @@ end
 C signature:
 `void gsl_integration_qk21 (const gsl_function * f, double a, double b, double *result, double *abserr, double *resabs, double *resasc)`
 """
-function integration_qk21(f, a, b, result, abserr, resabs, resasc)
+function integration_qk21(f::F, a, b, result, abserr, resabs, resasc) where F
     ccall((:gsl_integration_qk21, libgsl), Cvoid, (Ref{gsl_function}, Cdouble, Cdouble, Ref{Cdouble}, Ref{Cdouble}, Ref{Cdouble}, Ref{Cdouble}), f, a, b, result, abserr, resabs, resasc)
 end
 
@@ -273,7 +273,7 @@ end
 C signature:
 `void gsl_integration_qk31 (const gsl_function * f, double a, double b, double *result, double *abserr, double *resabs, double *resasc)`
 """
-function integration_qk31(f, a, b, result, abserr, resabs, resasc)
+function integration_qk31(f::F, a, b, result, abserr, resabs, resasc) where F
     ccall((:gsl_integration_qk31, libgsl), Cvoid, (Ref{gsl_function}, Cdouble, Cdouble, Ref{Cdouble}, Ref{Cdouble}, Ref{Cdouble}, Ref{Cdouble}), f, a, b, result, abserr, resabs, resasc)
 end
 
@@ -283,7 +283,7 @@ end
 C signature:
 `void gsl_integration_qk41 (const gsl_function * f, double a, double b, double *result, double *abserr, double *resabs, double *resasc)`
 """
-function integration_qk41(f, a, b, result, abserr, resabs, resasc)
+function integration_qk41(f::F, a, b, result, abserr, resabs, resasc) where F
     ccall((:gsl_integration_qk41, libgsl), Cvoid, (Ref{gsl_function}, Cdouble, Cdouble, Ref{Cdouble}, Ref{Cdouble}, Ref{Cdouble}, Ref{Cdouble}), f, a, b, result, abserr, resabs, resasc)
 end
 
@@ -293,7 +293,7 @@ end
 C signature:
 `void gsl_integration_qk51 (const gsl_function * f, double a, double b, double *result, double *abserr, double *resabs, double *resasc)`
 """
-function integration_qk51(f, a, b, result, abserr, resabs, resasc)
+function integration_qk51(f::F, a, b, result, abserr, resabs, resasc) where F
     ccall((:gsl_integration_qk51, libgsl), Cvoid, (Ref{gsl_function}, Cdouble, Cdouble, Ref{Cdouble}, Ref{Cdouble}, Ref{Cdouble}, Ref{Cdouble}), f, a, b, result, abserr, resabs, resasc)
 end
 
@@ -303,7 +303,7 @@ end
 C signature:
 `void gsl_integration_qk61 (const gsl_function * f, double a, double b, double *result, double *abserr, double *resabs, double *resasc)`
 """
-function integration_qk61(f, a, b, result, abserr, resabs, resasc)
+function integration_qk61(f::F, a, b, result, abserr, resabs, resasc) where F
     ccall((:gsl_integration_qk61, libgsl), Cvoid, (Ref{gsl_function}, Cdouble, Cdouble, Ref{Cdouble}, Ref{Cdouble}, Ref{Cdouble}, Ref{Cdouble}), f, a, b, result, abserr, resabs, resasc)
 end
 
@@ -313,7 +313,7 @@ end
 C signature:
 `void gsl_integration_qcheb (gsl_function * f, double a, double b, double *cheb12, double *cheb24)`
 """
-function integration_qcheb(f, a, b, cheb12, cheb24)
+function integration_qcheb(f::F, a, b, cheb12, cheb24) where F
     ccall((:gsl_integration_qcheb, libgsl), Cvoid, (Ref{gsl_function}, Cdouble, Cdouble, Ref{Cdouble}, Ref{Cdouble}), f, a, b, cheb12, cheb24)
 end
 
@@ -323,7 +323,7 @@ end
 C signature:
 `void gsl_integration_qk (const int n, const double xgk[], const double wg[], const double wgk[], double fv1[], double fv2[], const gsl_function *f, double a, double b, double * result, double * abserr, double * resabs, double * resasc)`
 """
-function integration_qk(n, xgk, wg, wgk, fv1, fv2, f, a, b, result, abserr, resabs, resasc)
+function integration_qk(n, xgk, wg, wgk, fv1, fv2, f::F, a, b, result, abserr, resabs, resasc) where F
     ccall((:gsl_integration_qk, libgsl), Cvoid, (Cint, Ref{Cdouble}, Ref{Cdouble}, Ref{Cdouble}, Ref{Cdouble}, Ref{Cdouble}, Ref{gsl_function}, Cdouble, Cdouble, Ref{Cdouble}, Ref{Cdouble}, Ref{Cdouble}, Ref{Cdouble}), n, xgk, wg, wgk, fv1, fv2, f, a, b, result, abserr, resabs, resasc)
 end
 
@@ -348,7 +348,7 @@ GSL documentation:
 > of function evaluations.
 
 """
-function integration_qng(f, a, b, epsabs, epsrel, result, abserr, neval)
+function integration_qng(f::F, a, b, epsabs, epsrel, result, abserr, neval) where F
     ccall((:gsl_integration_qng, libgsl), Cint, (Ref{gsl_function}, Cdouble, Cdouble, Cdouble, Cdouble, Ref{Cdouble}, Ref{Cdouble}, Ref{Csize_t}), f, a, b, epsabs, epsrel, result, abserr, neval)
 end
 
@@ -394,7 +394,7 @@ GSL documentation:
 > allocated size of the workspace.
 
 """
-function integration_qag(f, a, b, epsabs, epsrel, limit, key, workspace, result, abserr)
+function integration_qag(f::F, a, b, epsabs, epsrel, limit, key, workspace, result, abserr) where F
     ccall((:gsl_integration_qag, libgsl), Cint, (Ref{gsl_function}, Cdouble, Cdouble, Cdouble, Cdouble, Csize_t, Cint, Ref{gsl_integration_workspace}, Ref{Cdouble}, Ref{Cdouble}), f, a, b, epsabs, epsrel, limit, key, workspace, result, abserr)
 end
 
@@ -420,7 +420,7 @@ GSL documentation:
 > In this case a lower-order rule is more efficient.
 
 """
-function integration_qagi(f, epsabs, epsrel, limit, workspace, result, abserr)
+function integration_qagi(f::F, epsabs, epsrel, limit, workspace, result, abserr) where F
     ccall((:gsl_integration_qagi, libgsl), Cint, (Ref{gsl_function}, Cdouble, Cdouble, Csize_t, Ref{gsl_integration_workspace}, Ref{Cdouble}, Ref{Cdouble}), f, epsabs, epsrel, limit, workspace, result, abserr)
 end
 
@@ -443,7 +443,7 @@ GSL documentation:
 > and then integrated using the QAGS algorithm.
 
 """
-function integration_qagiu(f, a, epsabs, epsrel, limit, workspace, result, abserr)
+function integration_qagiu(f::F, a, epsabs, epsrel, limit, workspace, result, abserr) where F
     ccall((:gsl_integration_qagiu, libgsl), Cint, (Ref{gsl_function}, Cdouble, Cdouble, Cdouble, Csize_t, Ref{gsl_integration_workspace}, Ref{Cdouble}, Ref{Cdouble}), f, a, epsabs, epsrel, limit, workspace, result, abserr)
 end
 
@@ -466,7 +466,7 @@ GSL documentation:
 > and then integrated using the QAGS algorithm.
 
 """
-function integration_qagil(f, b, epsabs, epsrel, limit, workspace, result, abserr)
+function integration_qagil(f::F, b, epsabs, epsrel, limit, workspace, result, abserr) where F
     ccall((:gsl_integration_qagil, libgsl), Cint, (Ref{gsl_function}, Cdouble, Cdouble, Cdouble, Csize_t, Ref{gsl_integration_workspace}, Ref{Cdouble}, Ref{Cdouble}), f, b, epsabs, epsrel, limit, workspace, result, abserr)
 end
 
@@ -493,7 +493,7 @@ GSL documentation:
 > which may not exceed the allocated size of the workspace.
 
 """
-function integration_qags(f, a, b, epsabs, epsrel, limit, workspace, result, abserr)
+function integration_qags(f::F, a, b, epsabs, epsrel, limit, workspace, result, abserr) where F
     ccall((:gsl_integration_qags, libgsl), Cint, (Ref{gsl_function}, Cdouble, Cdouble, Cdouble, Cdouble, Csize_t, Ref{gsl_integration_workspace}, Ref{Cdouble}, Ref{Cdouble}), f, a, b, epsabs, epsrel, limit, workspace, result, abserr)
 end
 
@@ -527,7 +527,7 @@ GSL documentation:
 > region then this routine will be faster than `gsl_integration_qags`.
 
 """
-function integration_qagp(f, pts, npts, epsabs, epsrel, limit, workspace, result, abserr)
+function integration_qagp(f::F, pts, npts, epsabs, epsrel, limit, workspace, result, abserr) where F
     ccall((:gsl_integration_qagp, libgsl), Cint, (Ref{gsl_function}, Ref{Cdouble}, Csize_t, Cdouble, Cdouble, Csize_t, Ref{gsl_integration_workspace}, Ref{Cdouble}, Ref{Cdouble}), f, pts, npts, epsabs, epsrel, limit, workspace, result, abserr)
 end
 
@@ -566,7 +566,7 @@ GSL documentation:
 > ordinary 15-point Gauss-Kronrod integration rule.
 
 """
-function integration_qawc(f, a, b, c, epsabs, epsrel, limit, workspace, result, abserr)
+function integration_qawc(f::F, a, b, c, epsabs, epsrel, limit, workspace, result, abserr) where F
     ccall((:gsl_integration_qawc, libgsl), Cint, (Ref{gsl_function}, Cdouble, Cdouble, Cdouble, Cdouble, Cdouble, Csize_t, Ref{gsl_integration_workspace}, Ref{Cdouble}, Ref{Cdouble}), f, a, b, c, epsabs, epsrel, limit, workspace, result, abserr)
 end
 
@@ -595,7 +595,7 @@ GSL documentation:
 > Gauss-Kronrod integration rule is used.
 
 """
-function integration_qaws(f, a, b, t, epsabs, epsrel, limit, workspace, result, abserr)
+function integration_qaws(f::F, a, b, t, epsabs, epsrel, limit, workspace, result, abserr) where F
     ccall((:gsl_integration_qaws, libgsl), Cint, (Ref{gsl_function}, Cdouble, Cdouble, Ref{gsl_integration_qaws_table}, Cdouble, Cdouble, Csize_t, Ref{gsl_integration_workspace}, Ref{Cdouble}, Ref{Cdouble}), f, a, b, t, epsabs, epsrel, limit, workspace, result, abserr)
 end
 
@@ -645,7 +645,7 @@ GSL documentation:
 > integration.
 
 """
-function integration_qawo(f, a, epsabs, epsrel, limit, workspace, wf, result, abserr)
+function integration_qawo(f::F, a, epsabs, epsrel, limit, workspace, wf, result, abserr) where F
     ccall((:gsl_integration_qawo, libgsl), Cint, (Ref{gsl_function}, Cdouble, Cdouble, Cdouble, Csize_t, Ref{gsl_integration_workspace}, Ref{gsl_integration_qawo_table}, Ref{Cdouble}, Ref{Cdouble}), f, a, epsabs, epsrel, limit, workspace, wf, result, abserr)
 end
 
@@ -737,7 +737,7 @@ GSL documentation:
 > `cycle_workspace` as workspace for the QAWO algorithm.
 
 """
-function integration_qawf(f, a, epsabs, limit, workspace, cycle_workspace, wf, result, abserr)
+function integration_qawf(f::F, a, epsabs, limit, workspace, cycle_workspace, wf, result, abserr) where F
     ccall((:gsl_integration_qawf, libgsl), Cint, (Ref{gsl_function}, Cdouble, Cdouble, Csize_t, Ref{gsl_integration_workspace}, Ref{gsl_integration_workspace}, Ref{gsl_integration_qawo_table}, Ref{Cdouble}, Ref{Cdouble}), f, a, epsabs, limit, workspace, cycle_workspace, wf, result, abserr)
 end
 
@@ -793,7 +793,7 @@ GSL documentation:
 > table `t` and returns the result.
 
 """
-function integration_glfixed(f, a, b, t)
+function integration_glfixed(f::F, a, b, t) where F
     ccall((:gsl_integration_glfixed, libgsl), Cdouble, (Ref{gsl_function}, Cdouble, Cdouble, Ref{gsl_integration_glfixed_table}), f, a, b, t)
 end
 
@@ -890,7 +890,7 @@ GSL documentation:
 > set to `NULL`.
 
 """
-function integration_cquad(f, a, b, epsabs, epsrel, ws, result, abserr, nevals)
+function integration_cquad(f::F, a, b, epsabs, epsrel, ws, result, abserr, nevals) where F
     ccall((:gsl_integration_cquad, libgsl), Cint, (Ref{gsl_function}, Cdouble, Cdouble, Cdouble, Cdouble, Ref{gsl_integration_cquad_workspace}, Ref{Cdouble}, Ref{Cdouble}, Ref{Csize_t}), f, a, b, epsabs, epsrel, ws, result, abserr, nevals)
 end
 
@@ -957,7 +957,7 @@ GSL documentation:
 > `neval`.
 
 """
-function integration_romberg(f, a, b, epsabs, epsrel, result, neval, w)
+function integration_romberg(f::F, a, b, epsabs, epsrel, result, neval, w) where F
     ccall((:gsl_integration_romberg, libgsl), Cint, (Ref{gsl_function}, Cdouble, Cdouble, Cdouble, Cdouble, Ref{Cdouble}, Ref{Csize_t}, Ref{gsl_integration_romberg_workspace}), f, a, b, epsabs, epsrel, result, neval, w)
 end
 
@@ -1116,7 +1116,7 @@ GSL documentation:
 > approximated as
 
 """
-function integration_fixed(func, result, w)
+function integration_fixed(func::F, result, w) where F
     ccall((:gsl_integration_fixed, libgsl), Cint, (Ref{gsl_function}, Ref{Cdouble}, Ref{gsl_integration_fixed_workspace}), func, result, w)
 end
 

src/gen/direct_wrappers/gsl_min_h.jl

@@ -67,7 +67,7 @@ GSL documentation:
 > returns an error code of `GSL_EINVAL`.
 
 """
-function min_fminimizer_set(s, f, x_minimum, x_lower, x_upper)
+function min_fminimizer_set(s, f::gsl_function, x_minimum, x_lower, x_upper)
     ccall((:gsl_min_fminimizer_set, libgsl), Cint, (Ref{gsl_min_fminimizer}, Ref{gsl_function}, Cdouble, Cdouble, Cdouble), s, f, x_minimum, x_lower, x_upper)
 end
 
@@ -86,7 +86,7 @@ GSL documentation:
 > `f(x_minimum)`, `f(x_lower)` and `f(x_upper)`.
 
 """
-function min_fminimizer_set_with_values(s, f, x_minimum, f_minimum, x_lower, f_lower, x_upper, f_upper)
+function min_fminimizer_set_with_values(s, f::gsl_function, x_minimum, f_minimum, x_lower, f_lower, x_upper, f_upper)
     ccall((:gsl_min_fminimizer_set_with_values, libgsl), Cint, (Ref{gsl_min_fminimizer}, Ref{gsl_function}, Cdouble, Cdouble, Cdouble, Cdouble, Cdouble, Cdouble), s, f, x_minimum, f_minimum, x_lower, f_lower, x_upper, f_upper)
 end
 
@@ -301,7 +301,7 @@ end
 C signature:
 `int gsl_min_find_bracket(gsl_function *f,double *x_minimum,double * f_minimum, double *x_lower, double * f_lower, double *x_upper, double * f_upper, size_t eval_max)`
 """
-function min_find_bracket(f, x_minimum, f_minimum, x_lower, f_lower, x_upper, f_upper, eval_max)
+function min_find_bracket(f::F, x_minimum, f_minimum, x_lower, f_lower, x_upper, f_upper, eval_max) where F
     ccall((:gsl_min_find_bracket, libgsl), Cint, (Ref{gsl_function}, Ref{Cdouble}, Ref{Cdouble}, Ref{Cdouble}, Ref{Cdouble}, Ref{Cdouble}, Ref{Cdouble}, Csize_t), f, x_minimum, f_minimum, x_lower, f_lower, x_upper, f_upper, eval_max)
 end
 

src/gen/direct_wrappers/gsl_multiroots_h.jl

@@ -12,7 +12,7 @@
 C signature:
 `int gsl_multiroot_fdjacobian (gsl_multiroot_function * F, const gsl_vector * x, const gsl_vector * f, double epsrel, gsl_matrix * jacobian)`
 """
-function multiroot_fdjacobian(F, x, f, epsrel, jacobian)
+function multiroot_fdjacobian(F::Fn, x, f, epsrel, jacobian) where Fn
     ccall((:gsl_multiroot_fdjacobian, libgsl), Cint, (Ref{gsl_multiroot_function}, Ref{gsl_vector}, Ref{gsl_vector}, Cdouble, Ref{gsl_matrix}), F, x, f, epsrel, jacobian)
 end
 
@@ -81,7 +81,7 @@ GSL documentation:
 > is not modified by subsequent iterations.
 
 """
-function multiroot_fsolver_set(s, f, x)
+function multiroot_fsolver_set(s, f::gsl_multiroot_function, x)
     ccall((:gsl_multiroot_fsolver_set, libgsl), Cint, (Ref{gsl_multiroot_fsolver}, Ref{gsl_multiroot_function}, Ref{gsl_vector}), s, f, x)
 end
 
@@ -242,7 +242,7 @@ end
 C signature:
 `int gsl_multiroot_fdfsolver_set (gsl_multiroot_fdfsolver * s, gsl_multiroot_function_fdf * fdf, const gsl_vector * x)`
 """
-function multiroot_fdfsolver_set(s, fdf, x)
+function multiroot_fdfsolver_set(s, fdf::gsl_multiroot_function_fdf, x)
     ccall((:gsl_multiroot_fdfsolver_set, libgsl), Cint, (Ref{gsl_multiroot_fdfsolver}, Ref{gsl_multiroot_function_fdf}, Ref{gsl_vector}), s, fdf, x)
 end
 

src/gen/direct_wrappers/gsl_roots_h.jl

@@ -66,7 +66,7 @@ GSL documentation:
 > `x_upper`\].
 
 """
-function root_fsolver_set(s, f, x_lower, x_upper)
+function root_fsolver_set(s, f::gsl_function, x_lower, x_upper)
     ccall((:gsl_root_fsolver_set, libgsl), Cint, (Ref{gsl_root_fsolver}, Ref{gsl_function}, Cdouble, Cdouble), s, f, x_lower, x_upper)
 end
 
@@ -221,7 +221,7 @@ GSL documentation:
 > use the function and derivative `fdf` and the initial guess `root`.
 
 """
-function root_fdfsolver_set(s, fdf, root)
+function root_fdfsolver_set(s, fdf::gsl_function_fdf, root)
     ccall((:gsl_root_fdfsolver_set, libgsl), Cint, (Ref{gsl_root_fdfsolver}, Ref{gsl_function_fdf}, Cdouble), s, fdf, root)
 end