To formulate my question a bit more specifically (about the last part of my email)
Suppose I want to call jl_new_struct() to instantiate a 'type', I need to provide the type, so I guess I have to pass the right jl_datatype_t *, which might be found with jl_get_global(). Now, jl_get_global() needs the module pointer, which is not available as a linking symbol sin this would come from an external module (let's say called MyModule). Is there a function to lookup the pointer of a module given its string name? Thanks. El sábado, 8 de febrero de 2014 21:10:11 UTC+1, Carlos Becker escribió: > > Hi Jeff, thanks for the quick reply. > > If "Any" is used as the return type of the ccall, the result will be >> treated as a julia reference and you can skip >> unsafe_pointer_to_objref. >> > > If returning "Any", would the GC take care of it? > > >> >> A variant of this is to allocate the array in julia, and pass it to >> the C function to be filled in (ccall will effectively call >> jl_array_ptr for you to pass the array to C). >> > > Right, but if the final size is not known before ccall(), then it may not > be as easy as creating it from C. > > Now, I am also looking for something a bit more involved. > For example, I need to return what in C is an array of structs > (std::vector<struct type>). > Do you see some problems when creating and filling a specific Julia type, > to add several of them > into a Julia array? Would you point me to some of the functions of the API > that could be used for this? > > Thanks, > Carlos > > > > >> >> On Sat, Feb 8, 2014 at 2:21 PM, Carlos Becker <carlos...@gmail.com> >> wrote: >> > Hello everyone, >> > >> > I just got started with Julia, and I wanted to try to wrap a C/C++ >> library >> > to Julia to check whether it would work out for my purposes. >> > >> > I tried out many ways of passing arrays and other objects from C back >> to >> > Julia. >> > So far it seems that it takes a lot of extra code if I want to return, >> for >> > example, a simple double-array or an array of types (eg structs). >> > >> > Then I thought that I could call the Julia API from the ccalled binary, >> to >> > allocate an array and return it to julia, >> > then use unsafe_pointer_to_objref() and get a neat Julia object >> directly. >> > >> > You can see a very simple example here >> > https://gist.github.com/anonymous/8888647 >> > >> > This would simplify _significantly_ a lot of code from the C side, at >> least >> > with what I am working right now. >> > >> > Now, my question is: is it safe to call functions such as >> > jl_alloc_array_1d() from the C binary? >> > would this be a problem in some situations? >> > >> > I understand that it may mess memory up if those functions are called >> > outside the main thread, but I would certainly not do that. >> > >> > Thanks in advance, >> > Carlos >> >
