Problem with dll called in JSFL

I need to create dll using C. But I saw some problems. OK, first: I need function in dll library to compute angle of the line - tgA = dy/dx. Angle = arctg(dy/dx). And I define this in file framework.c:

JSBool computeAngle(JSContext *cx, 
                    JSObject *obj, 
                    unsigned int argc, 
                    jsval *argv, 
                    jsval *rval ) {
double dx, dy, angle;
if (argc != 2) {
    return JS_FALSE;
}
if (JS_ValueToDouble(cx, argv[0], &dy) == JS_FALSE ||
        JS_ValueToDouble(cx, argv[1], &dx) == JS_FALSE) {
    return JS_FALSE;
}
if( dx == 0 开发者_如何学Go) {
    if( dy < 0 ) angle = -90;
    else if( dy > 0 ) angle = 90;
    else angle = 0;
}else angle = atan(dy/dx)*180/M_PI;
return JS_DoubleToValue(cx, angle, rval);
}

But this method doesn't work! I thought that something wrong, and downloaded Sample.zip from Adobe site. I chanded function computeSum on my function, but it still not work. I think that something wrong with JS_ValueToDouble() and JS_DoubleToValue methods. How do you think?

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Which part of this method doesn't work? Calling the method inside the dll from another set of code (eg. you've compiled your DLL and created a test program, but it throws linker errors), or you can't compile your dll? If it's the first, your method needs something like the following macro defined:

#ifdef EXPORT
#define DLL_EXPORT __declspec(dllexport)
#else
#define DLL_EXPORT __declspec(dllimport)
#endif

In your header (or if the function is not declared in a header, in the C file), you'll require

DLL_EXPORT JSBool computeAngle(JSContext *cx, 
                               JSObject *obj, 
                               unsigned int argc, 
                               jsval *argv, 
                               jsval *rval )

If the error lies when trying to compile your dll, there's a high chance you're not linking to the dll properly - you need to set Project Linker properties (if using MSVS) or use the -l option if using MinGW.