ffi_open


ffi_open(libname)

Return an object representing a "handle" to the shared library file named libname, false if the shared library could not be loaded.

Examples:

Imagine we want our Slogan program to call the function defined in the following C program:


// test.c
          
#include <stdio.h>
#include "slogan.h"
  
___slogan_obj say_hello(___slogan_obj *args)
{
  ___slogan_obj message;
  char *s = "hello from C!";
  char *p;
  ___slogan_obj_to_charstring(args[0], &p);
  printf("Slogan says \"%s\"\n", p);
      
  ___charstring_to_slogan_obj(s, &message);
  return message;
}

This can be compiled to a shared library on Linux by,


$ gcc -Wall -shared -fPIC -I ${SLOGAN_HOME}/src/include/-I ${SLOGAN_HOME}/platform/gsc/include \
-o test.so test.c

and on OS X by,


$ gcc -dynamiclib -Wl,-undefined -Wl,dynamic_lookup -I ${SLOGAN_HOME}/src/include/ \
-I ${SLOGAN_HOME}/platform/gsc/include -o test.so test.c

After the shared library test.so is generated, the function say_hello can be invoked from Slogan as shown below:


let clib = ffi_open("./test.so")
let f = ffi_fn(clib, "say_hello")
ffi_call_obj(f, #["hello from Slogan"])
//> Slogan says "hello from Slogan"
// hello from C!
ffi_close(clib)
// true

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