Kotlin native - Execute an executable - kotlin

Question

I am trying to execute a command via bash, for example konanc.
In KotlinJVM this would just be using Runtime.getRuntime().exec("..."), or creating a Process using the ProcessBuilder, however, none of those classes are available in Kotlin-Native, as they are part of the Java libraries.
I tried searching for example code in the documentation and the kotlin-native GitHub repository, but haven't found anything.

Answer 1

tl;dr No, there is no standard process api for kotlin-native
Well the kotlin std for native is still under development, and i don't think process api will be there anytime soon.
However you could use interoperability with some C process library such as https://github.com/eidheim/tiny-process-library
How-to you will find here https://github.com/JetBrains/kotlin-native/blob/master/INTEROP.md
However there are also POSIX's exec/fork calls you could use to spawn and create new process and i think kotlin-native does include POSIX for linux/windows. https://github.com/JetBrains/kotlin-native/tree/master/platformLibs/src/platform see posix.def for platforms.
Example:
import platform.posix.*
fun main(arguments: Array<String>) {
println("${arguments[0]}")
execlp("touch", "touch", "${arguments[0]}")
}
Calling it with ./file <name> will create a file that is named after the parameter name in your current directory.

Answer 2

IMHO, this is the killer app for Kotlin native. And here is part of the solution using the standard Kotlin API; This solution still needs the buffering of the dir or date command output, but generally works on Windows yea!
import kotlin.native.OsFamily.*
import platform.posix.*
fun main(arguments: Array<String>) {
println("running")
if (arguments.size >= 1) {
arguments.forEach { a -> println(a) }
}
val platform = Platform
val os = platform.osFamily
println("os is " + os)
when (os) {
WINDOWS -> runWindows()
else -> runUnix()
}
}
fun runWindows() {
val result = execlp("dir", "","")
println("Ran on windows $result");
}
fun runUnix() {
execlp("date", "","")
println("Ran on UNIX")
}

Answer 3

Finally one that reads from the called process yea!
Only tested on Windows, I will do unix (aka mac :) ) tomorrow.
import kotlin.native.OsFamily.*
import platform.posix.*
import kotlinx.cinterop.refTo
import kotlinx.cinterop.toKString
fun main(arguments: Array<String>) {
println("running")
if (arguments.size >= 1) {
arguments.forEach { a -> println(a) }
}
val platform = Platform
val os = platform.osFamily
println("os is " + os)
when (os) {
WINDOWS -> runWindows()
else -> runUnix()
}
}
fun runWindows() {
val result = execl("dir", "","")
//hmm emulate https://gist.github.com/a-cordier/33211eda92b8084a9e7e
//https://www.youtube.com/watch?v=6xbLgZpOBi8
val fp = _popen("dir", "r") ?: error("Failed to run command: dir")
val buffer = ByteArray(4096)
var counter = 0
println("hmm")
while (true) {
val input = fgets(buffer.refTo(0), buffer.size, fp) ?: break
print(input.toKString())
//println(counter++)
}
println("Ran on windows $result");
}
fun runUnix() {
execlp("date", "","")
println("Ran on UNIX")
}