Hi, I'm trying to call the following C function from Julia using ccall
void sum(Problem *P) { int i; printf("n = %d, res = %g\n", P->n, P->res); for (i = 0; i < P->n; i++) { P->res += P->x[i]; printf("x[i] = %g, res = %g\n", P->x[i], P->res); } } which takes as argument the following struct typedef struct Problem { int n; double *x; double res; } Problem; My Julia code is type Problem n::Cint x::Ref{Cdouble} res::Cdouble end x = [1.3, 2.7, 4.9] p = Problem(length(x), x, 0.) ccall((:sum, "test"), Void, (Ref{Problem},), p) println(p.res) While I can read the n and res variables from inside the C function, I can't read the x array. According to http://docs.julialang.org/en/release-0.4/manual/calling-c-and-fortran-code/, "arrays of unknown size are not supported.". Is that the case here? Does anyone know if it would be too hard to lift this restriction? Thanks, Andre