Mixed Parameter Types - ArkFFI

C functions often accept parameters of different types. arkffi handles this by separating numeric and string arguments into two arrays.

Signature Encoding

Code	C Type
`i`	`int32_t`, `int`, `bool`, `char`
`l`	`int64_t`, `uint64_t`, `void*`
`d`	`double`, `float`
`s`	`const char*`

For a function like:

double compute(int mode, double value, const char* name);

The type string is "ids" and the return type is "d".

Using `callMixed`

const h = ffi.load('libffi_target.so');

const result = ffi.callMixed(
  h, 'compute',
  'ids',       // arg types: int32, double, CString
  'd',         // return type: double
  [0, 4.0],    // numeric args
  ['square'],  // string args
);

ffi.close(h);

Using `dlopen`

const lib = dlopen('libffi_target.so', {
  compute: {
    args: [FFIType.int32, FFIType.double, FFIType.CString],
    returns: FFIType.double,
  },
});

lib.symbols.compute(0, 4.0, 'square');

Supported Signatures

Signature	C Function
`id`	`double fn(int32_t, double)`
`di`	`double fn(double, int32_t)`
`ids`	`double fn(int32_t, double, const char*)`
`sid`	`double fn(const char*, int32_t, double)`
`isd`	`double fn(int32_t, const char*, double)`
`iid`	`double fn(int32_t, int32_t, double)`
`idi`	`double fn(int32_t, double, int32_t)`
`idid`	`double fn(int32_t, double, int32_t, double)`
`ss`	`int32_t fn(const char, const char)`
`s`	`double fn(const char*)`