While Julia can rightfully claim to obviate the need to write some C or FORTRAN code, it is possible that you will need to interact with the existing C or FORTRAN shared libraries. Functions in such a library can be called directly by Julia, with no glue code, or boilerplate code or compilation needed. Because Julia's LLVM compiler generates native code, calling a C function from Julia has exactly the same overhead as calling the same function from C code itself. However, first, we need to know a few more things:
For calling out to C, we need to work with pointer types; a native pointer
Ptr{T}is nothing more than the memory address for a variable of typeTAt this lower level, the term
bitstypeis also used;bitstypeis a concrete type whose data consists of bits, such asInt8,Uint8,Int32,Float64,Bool, andCharTo pass a string to C, it is converted to a contiguous byte array representation with the function
bytestring(); givenPtrto a C string, it returns a Julia...