Given a kernel object with children objects, obtain a handle to the child specified by the provided kernel object id.
#include <zircon/syscalls.h> zx_status_t zx_object_get_child(zx_handle_t handle, uint64_t koid, zx_rights_t rights, zx_handle_t* out);
zx_object_get_child() attempts to find a child of the object referred to
by handle which has the kernel object id specified by koid. If such an
object exists, and the requested rights are not greater than those provided
by the handle to the parent, a new handle to the specified child object is
rights may be ZX_RIGHT_SAME_RIGHTS which will result in rights equivalent to the those on the handle.
If the object is a Process, the Threads it contains may be obtained by this call.
If the object is a Job, its (immediate) child Jobs and the Processes it contains may be obtained by this call.
handle must have ZX_RIGHT_ENUMERATE.
On success, ZX_OK is returned and a handle to the desired child object is returned via out.
ZX_ERR_BAD_HANDLE handle is not a valid handle.
ZX_ERR_WRONG_TYPE handle is not a Process, Job, or Resource.
ZX_ERR_ACCESS_DENIED handle lacks the right ZX_RIGHT_ENUMERATE or rights specifies rights that are not present on handle.
ZX_ERR_NOT_FOUND handle does not have a child with the kernel object id koid.
ZX_ERR_NO_MEMORY Failure due to lack of memory. There is no good way for userspace to handle this (unlikely) error. In a future build this error will no longer occur.
ZX_ERR_INVALID_ARGS out is an invalid pointer.