Simple Example (libffi: the portable foreign function interface library)

2.2 Simple Example

Here is a trivial example that calls puts a few times.

#include <stdio.h>
#include <ffi.h>

int main()
{
  ffi_cif cif;
  ffi_type *args[1];
  void *values[1];
  char *s;
  ffi_arg rc;

  /* Initialize the argument info vectors */
  args[0] = &ffi_type_pointer;
  values[0] = &s;

  /* Initialize the cif */
  if (ffi_prep_cif(&cif, FFI_DEFAULT_ABI, 1,
		       &ffi_type_sint, args) == FFI_OK)
    {
      s = "Hello World!";
      ffi_call(&cif, puts, &rc, values);
      /* rc now holds the result of the call to puts */

      /* values holds a pointer to the function's arg, so to
         call puts() again all we need to do is change the
         value of s */
      s = "This is cool!";
      ffi_call(&cif, puts, &rc, values);
    }

  return 0;
}