glib:variant-handle (value)

value -- a g:variant instance with a handle

The :int32 value.

Returns the 32-bit signed integer of value. It is an error to call this function with a value of any type other than a g:variant-type type with the "h" type string.

By convention, handles are indexes into an array of file descriptors that are sent alongside a D-Bus message. If you are not interacting with D-Bus, you probably do not need them.