从传递浮点数组的C函数调用Objective C函数

Question

I´m trying to pass a reference of array of floats. The problem is the call, because I´am developing for c but I want to make a call to an Objective C Function, Could anyone help me? How can I make the call? There you have the code:

bool VideoCamera_Camera(float *buffer) {
    [VideoCameraBinded VideoCamera_CameraUpdateBinded: buffer];
}

Thank you

Answer 1

I'm going to assume that VideoCameraBinded is an instance, and not a class. If I am mistaken, please let me know.

If you have a method defined on VideoCameraBinded's class, something like this:

- (void)VideoCamera_CameraUpdateBinded:(float *)buffer {
//...
}

then I don't know where your problem is coming from. Are you getting a specific error or some other issue?

Answer 2

If you have access to and can change the Objective-C code, add a C API there.

Otherwise, if you really can't change the Objective-C code you can use the Objective-C runtime directly, but this is discouraged:

#include <objc/runtime.h>

objc_msgSend(VideoCameraBinded, // receiver
             sel_registerName("VideoCamera_CameraUpdateBinded:"), // selector
             buffer); // comma separated list of arguments

You need to link to an Objective-C runtime library, usually libobjc:

$ clang mycode.c -lobjc
$ # or cc if you use GCC

---

If the Objective-C method expects an NSArray * instead of a float * , you can use Core Foundation with CFArrayRef . CFArrayRef and NSArray * are interchangeable, but CFArrayRef is a C type so you can use that. Same goes for CFNumberRef and NSNumber * , see Apple's documentation on this .

Answer 3

What is the parameter type for VideoCamera_CameraUpdateBinded: ?

If its NSArray then you have to loop, create an array and send it like any other obj-c method. You'll have to store the floats in some kind of objects (eg NSNumber ).

Otherwise, if the obj-c function is taking a float* then you should be good to go.

BTW, shouldn't you pass a bufferSize parameter too?