Function libffi::low::prep_cif

pub unsafe fn prep_cif(cif: *mut ffi_cif,
                       abi: ffi_abi,
                       nargs: usize,
                       rtype: *mut ffi_type,
                       atypes: *mut *mut ffi_type)
                       -> Result<()>

Initalizes a CIF (Call Interface) with the given ABI and types.

We need to initialize a CIF before we can use it to call a function or create a closure. This function lets us specify the calling convention to use and the argument and result types. For varargs CIF initialization, see prep_cif_var.

Safety

The CIF cif retains references to rtype and atypes, so if they are no longer live when the CIF is used then the behavior is undefined.

Arguments

• cif — the CIF to initialize
• abi — the calling convention to use
• nargs — the number of arguments
• rtype — the result type
• atypes — the argument types (length must be at least nargs)

Result

Ok(()) for success or Err(e) for failure.

Examples

use libffi::low::*;

let mut args: [*mut ffi_type; 2] = unsafe {
    [ &mut types::sint32,
      &mut types::uint64 ]
};
let mut cif: ffi_cif = Default::default();

unsafe {
    prep_cif(&mut cif, ffi_abi_FFI_DEFAULT_ABI, 2,
             &mut types::pointer, args.as_mut_ptr())
}.unwrap();