c/c++语言开发共享在Swift中使用C函数，将函数作为参数

我正在写一个C数学库的包装器。 每个函数都将一个或两个函数作为参数。 但是，这些子函数（以及父函数）的参数不是Swifty -hence包装器。

我已经清理了示例代码，只显示了三个主要部分：c-library函数，将传递给包装器的所需Swift函数（未显示主体，但环绕c-library函数），以及必需的C函数forms。

//C library function, that calls the passed function dozens, hundreds or thousands of times, each time it changes the data provided in p, and uses the output from x //The Swift arrays are passed as pointers, and the length of the and x array are m and n respectively returnValue = cLibraryFunc(passedFunc, &p, &x, Int32(m), Int32(n), Int32(itmax), &opts, &info, &work, &covar, &adata) //I would like to create a Swift function that would look like this (internals could be any myriad of things that takes inputs p and adata and returns data in x: func desiredSwifty(p: inout [Double], x: inout [Double], m: Int, n: Int, adata: inout [Double]) { //very simple example //this example knows the length of p (so m as well) //and assumes that adata length is the same as the x length (n) //obviously, it could ifer m and n from p.count and x.count for i in 0..<n { x[i] = p[0] + p[1]*adata[i] + p[2]*pow(adata[i], 2) } } //And the wrapper would "convert" it -internally- into the form that the C library function requires: func requiredC(p: UnsafeMutablePointer?, x: UnsafeMutablePointer?, m: Int32, n: Int32, adata: UnsafeMutablePointer?) { //same thing, but using pointers, and uglier //first, have to bitcast the void back to a double let adataDouble : UnsafeMutablePointer = unsafeBitCast(adata, to: UnsafeMutablePointer.self) for i in 0..<Int(n) { x![i] = p![0] + p![1]*adataDouble[i] + p![2]*pow(adataDouble[i], 2) } } 

加成

我应该补充说我可以访问c源代码，所以我可以添加一些虚拟参数（可能是为了找到传递上下文的方法）。 但鉴于文档似乎表明无法使用ac函数指针获取上下文，这可能毫无用处。

 // cfunction.h: void cFunc(void (*func)(double *values, int count)); // cfunction.c: void cFunc(void (*func)(double *values, int count)) { double x[] = { 1.2, 3.4, 5,6 }; func(x, 3); } 

 func cFunc(_ func: (@convention(c) (UnsafeMutablePointer?, Int32) -> Swift.Void)!) 

 func swiftyFunc(passedFunc: (@convention(c) (UnsafeMutablePointer?, Int32) -> Void)) { cFunc(passedFunc) } 

 func functionToPass(values: UnsafeMutablePointer?, count: Int32) { let bufPtr = UnsafeBufferPointer(start: values, count: Int(count)) for elem in bufPtr { print(elem) } } swiftyFunc(passedFunc: functionToPass) 

 swiftyFunc { (values, count) in let bufPtr = UnsafeBufferPointer(start: values, count: Int(count)) for elem in bufPtr { print(elem) } } 

 func foo(_ x: UnsafeMutablePointer) { print(x) } func bar(_ x: UnsafeMutablePointer) { print(x) } var array = [0] foo(&array) var int = 0 bar(&int) 

以上就是c/c++开发分享在Swift中使用C函数，将函数作为参数相关内容,想了解更多C/C++开发(异常处理)及C/C++游戏开发关注计算机技术网(www.ctvol.com)!)。