Javascript 需要一个Firefox ctypes输出字符串参数的工作示例

嗨，我有一个XPCOM组件，我现在正在转换为使用ctypes

我能够创建采用wchar_t*的函数，并使用ctypes.jschar.ptr定义函数。 这一切都很好，但是当我需要创建wchar\t指针和指针数组时，如何使用输出参数呢

我读了很多书，我很困惑

我应该如何分配内存 在我的C dll中？我应该用吗 马洛克？如果是这样的话，那会怎样呢 释放

您将如何分配和处理 wchar_t*的out参数？我会吗 从javascript将其作为 CData我以前迟到过吗

我应该如何处理wchar\t字符串 阵列

谁能给我一些代码示例，比如如何处理这样的函数？ （无论是在C端，使用malloc？还是在javascript端，我应该使用什么来分配内存，这应该如何处理）

---

谢谢

我想我可以帮你回答第二个问题

在C端，接受输出参数的方法如下所示：

const char* useAnOutputParam(const char** outParam) {
    const char* str = "You invoked useAnOutputParam\0";
    const char* outStr = "This is your outParam\0";
    *outParam = outStr;
    return str;
}

在JavaScript方面：

Components.utils.import("resource://gre/modules/ctypes.jsm");

/**
 * PlayingWithJsCtypes namespace.
 */
if ("undefined" == typeof(PlayingWithJsCtypes)) {
  var PlayingWithJsCtypes = {};
};


var myLib = {
    lib: null,

    init: function() {
        //Open the library you want to call
        this.lib = ctypes.open("/path/to/library/libTestLibraryC.dylib");

        //Declare the function you want to call
        this.useAnOutputParam = this.lib.declare("useAnOutputParam",
                        ctypes.default_abi,
                        ctypes.char.ptr,
                        ctypes.char.ptr.ptr);

    },

    useAnOutputParam: function(outputParam) {
        return this.useAnOutputParam(outputParam);
    },

    //need to close the library once we're finished with it
    close: function() {
        this.coreFoundationLib.close();
    }
};

PlayingWithJsCtypes.BrowserOverlay = {

    /*
     * This is called from the XUL code
     */
    doSomething : function(aEvent) {
        myLib.init();

        //Instantiate the output parameter
        let outputParam = new ctypes.char.ptr();

        //Pass through the address of the output parameter
        let retVal = myLib.useAnOutputParam(outputParam.address());
        alert ("retVal.readString() " + retVal.readString());
        alert ("outputParam.toString() " + outputParam.readString());

        myLib.close();
    }
};

该论坛帖子有助于：

Components.utils.import("resource://gre/modules/ctypes.jsm");

/**
 * PlayingWithJsCtypes namespace.
 */
if ("undefined" == typeof(PlayingWithJsCtypes)) {
  var PlayingWithJsCtypes = {};
};


var myLib = {
    lib: null,

    init: function() {
        //Open the library you want to call
        this.lib = ctypes.open("/path/to/library/libTestLibraryC.dylib");

        //Declare the function you want to call
        this.useAnOutputParam = this.lib.declare("useAnOutputParam",
                        ctypes.default_abi,
                        ctypes.char.ptr,
                        ctypes.char.ptr.ptr);

    },

    useAnOutputParam: function(outputParam) {
        return this.useAnOutputParam(outputParam);
    },

    //need to close the library once we're finished with it
    close: function() {
        this.coreFoundationLib.close();
    }
};

PlayingWithJsCtypes.BrowserOverlay = {

    /*
     * This is called from the XUL code
     */
    doSomething : function(aEvent) {
        myLib.init();

        //Instantiate the output parameter
        let outputParam = new ctypes.char.ptr();

        //Pass through the address of the output parameter
        let retVal = myLib.useAnOutputParam(outputParam.address());
        alert ("retVal.readString() " + retVal.readString());
        alert ("outputParam.toString() " + outputParam.readString());

        myLib.close();
    }
};