Kotlin/Native尝试

Kotlin/Native尝试

在官网看到Kotlin/Native已经达到1.0 Beta版于是就去尝试了一下，结果发现坑还是挺多的。

首先Kotlin/JVM很多库是用不了的，这个已经猜到了。官网说已经预先导入了 POSIX、 gzip、 OpenGL、 Metal、 Foundation 等很多其他的库，然后我就尝试了下基本的文件读写。和C还是有一点的差别的。如下：

fun hello(): String = "Hello, Kotlin/Native!"
fun letter() = "abcdefghigklmnopqrstuvwxyz"

fun main(args: Array<String>) {
    val file = fopen("data.txt", "w")
    fprintf(file, "%s", hello())
    fprintf(file, "%s", "\n")
    fprintf(file, "%s", letter())
    fclose(file)
    println("write finished")
    val filer = fopen("data.txt", "r")
    val buf = ByteArray(255)
//    fscanf(filer, "%s", buf.pin().addressOf(0))
    fgets(buf.pin().addressOf(0), 255, filer)
    fclose(filer)
    print(buf.stringFromUtf8())
    buf.pin().unpin()
    println("read finished")
    system("pause")
}

运行结果如下

> Task :runProgram
write finished
Hello, Kotlin/Native!
read finished
Press any key to continue . . . 
C:\BuildAgent\work\4d622a065c544371\runtime\src\main\cpp\Memory.cpp:1150: runtime assert: Memory leaks found

> Task :runProgram FAILED

令人郁闷的是提示 C:\BuildAgent\work\4d622a065c544371\runtime\src\main\cpp\Memory.cpp:1150: runtime assert: Memory leaks found ，虽然调用了 buf.pin().unpin() ，但依旧提示内存泄漏，也没有异常退出啊。

如果是改成如下方式就不会提示错误了：

fun hello(): String = "Hello, Kotlin/Native!"
fun letter() = "abcdefghigklmnopqrstuvwxyz"

fun main(args: Array<String>) {
    val file = fopen("data.txt", "w")
    fprintf(file, "%s", hello())
    fprintf(file, "%s", "\n")
    fprintf(file, "%s", letter())
    fclose(file)
    println("write finished")
    val filer = fopen("data.txt", "r")
    val buf = ByteArray(255)
//    fscanf(filer, "%s", buf.pin().addressOf(0))
//    fgets(buf.pin().addressOf(0), 255, filer)
//    fclose(filer)
//    print(buf.stringFromUtf8())
//    buf.pin().unpin()
    buf.usePinned {
        fgets(it.addressOf(0), 255, filer)
        fclose(filer)
        print(buf.stringFromUtf8())
    }
    println("read finished")
    system("pause")
}

结果如下：

> Task :runProgram
write finished
Hello, Kotlin/Native!
read finished
Press any key to continue . . . 

BUILD SUCCESSFUL in 9s

另外吐槽下，这么几行代码就要9s，是不是太慢了。

随后又试了下开启pthread线程，但是 pthread_create 函数的第一个参数 th: kotlinx.cinterop.CValuesRef<platform.posix.pthread_tVar> ， CValuesRef 类型的变量怎么获得一直误解，难道只能通过继承获得？

然后我在写文章的时候又发现只要这样写就可以了？？？

fun main(args: Array<String>) {
    pthread_create(null, null, test(), null)
}

typealias func = kotlinx.cinterop.CPointer<kotlinx.cinterop.CFunction<(kotlinx.cinterop.COpaquePointer?) -> kotlinx.cinterop.COpaquePointer?>>?

fun test(): func {
    return staticCFunction<kotlinx.cinterop.COpaquePointer?, kotlinx.cinterop.COpaquePointer?> {
        println("run test")
        it
    }
}

结果如下：

> Task :runProgram
run test
BUILD SUCCESSFUL in 8s

> Task :runProgram
write finished
Hello, Kotlin/Native!
read finished
Press any key to continue . . . 
C:\BuildAgent\work\4d622a065c544371\runtime\src\main\cpp\Memory.cpp:1150: runtime assert: Memory leaks found

令人郁闷的是它提示``