Question

我在C库中有API，如下所示

EXPORT void test(char *a) {
    // Do something to change value of "a"
}

我想用node-ffi和ref将字符串指针传递给该API。我尝试了很多方法，但没有成功。还有其他人可以帮我解决吗？

Answer 1

你打算如何防止缓冲区溢出？大多数输出字符串的函数也会使用一个参数来指定为该字符串分配的最大长度。这个问题不可能，以下对我有用：

//use ffi and ref to interface with a c style dll
var ffi = require('ffi');
var ref = require('ref');

//load the dll. The dll is located in the current folder and named customlib.dll
var customlibProp = ffi.Library('customlib', {
    'myfunction': [ 'void', [ 'char *' ] ]
});

var maxStringLength = 200;
var theStringBuffer = new Buffer(maxStringLength);
theStringBuffer.fill(0); //if you want to initially clear the buffer
theStringBuffer.write("Intitial value", 0, "utf-8"); //if you want to give it an initial value

//call the function
customlibProp.myfunction(theStringBuffer);

//retrieve and convert the result back to a javascript string
var theString = theStringBuffer.toString('utf-8');
var terminatingNullPos = theString.indexOf('\u0000');
if (terminatingNullPos >= 0) {theString = theString.substr(0, terminatingNullPos);}
console.log("The string: ",theString);

我也不肯定你的c函数有正确的声明。我正在接口的功能有一个签名，就像： void (__stdcall *myfunction)(char *outputString); 也许EXPORT可以解决同样的问题，我最近还没有完成任何c编程以便记住。

node-ffi - 将字符串指针传递给C库

1 个答案: