https://www.graalvm.org/ 
class com.oracle.svm.driver.Unistd
  minor version: 0
  major version: 59
  flags: flags: (0x0020) ACC_SUPER
  this_class: com.oracle.svm.driver.Unistd
  super_class: java.lang.Object
{
  void <init>();
    descriptor: ()V
    flags: (0x0000) 
    Code:
      stack=1, locals=1, args_size=1
        start local 0 // com.oracle.svm.driver.Unistd this
         0: .line 85
            aload 0 /* this */
            invokespecial java.lang.Object.<init>:()V
            return
        end local 0 // com.oracle.svm.driver.Unistd this
      LocalVariableTable:
        Start  End  Slot  Name  Signature
            0    1     0  this  Lcom/oracle/svm/driver/Unistd;

  public static native int setsid();
    descriptor: ()I
    flags: (0x0109) ACC_PUBLIC, ACC_STATIC, ACC_NATIVE
    RuntimeVisibleAnnotations: 
      org.graalvm.nativeimage.c.function.CFunction()

  public static native int getsid(int);
    descriptor: (I)I
    flags: (0x0109) ACC_PUBLIC, ACC_STATIC, ACC_NATIVE
    RuntimeVisibleAnnotations: 
      org.graalvm.nativeimage.c.function.CFunction()
    MethodParameters:
      Name  Flags
      pid   

  public static native long gethostid();
    descriptor: ()J
    flags: (0x0109) ACC_PUBLIC, ACC_STATIC, ACC_NATIVE
    RuntimeVisibleAnnotations: 
      org.graalvm.nativeimage.c.function.CFunction()

  public static native int fork();
    descriptor: ()I
    flags: (0x0109) ACC_PUBLIC, ACC_STATIC, ACC_NATIVE
    RuntimeVisibleAnnotations: 
      org.graalvm.nativeimage.c.function.CFunction()
}
SourceFile: "NativeImageServerHelper.java"
    RuntimeVisibleAnnotations: 
      org.graalvm.nativeimage.Platforms(value = {Lorg/graalvm/nativeimage/Platform$LINUX;, Lorg/graalvm/nativeimage/Platform$DARWIN;})
      org.graalvm.nativeimage.c.CContext(value = Lcom/oracle/svm/driver/UnistdDirectives;)