Re: cdata finalizer called twice
- From: Peter Colberg <peter@xxxxxxxxxxx>
- To: luajit@xxxxxxxxxxxxx
- Date: Sun, 16 Nov 2014 16:54:24 -0500
On Sun, Nov 16, 2014 at 02:03:05AM -0500, Peter Colberg wrote:
> Finally I discovered why some cdata objects were finalized twice.
Does the following function return a reference to an unanchored cdata?
local uint64_t = ffi.typeof("uint64_t")
local uint64_t_1 = ffi.typeof("uint64_t[1]")
local function get_event_profiling_info_start(event)
local value = uint64_t_1()
assert(0 == C.clGetEventProfilingInfo(event, C.CL_PROFILING_COMMAND_START,
ffi.sizeof(uint64_t), value, nil))
return value[0]
end
If I change these functions to explicitly make a copy,
local function get_event_profiling_info_start(event)
local value = uint64_t_1()
assert(0 == C.clGetEventProfilingInfo(event, C.CL_PROFILING_COMMAND_START,
ffi.sizeof(uint64_t), value, nil))
return uint64_t(value[0])
end
the duplicate finalization is resolved, too.
Consider the following example:
local ffi = require("ffi")
local count = 0
local buf = ffi.new("uint64_t[1]")
local function inc()
count = count + 1
buf[0] = count
return buf[0]
end
local v1 = inc()
local v2 = inc()
local v3 = inc()
print(v1, v2, v3) -- 1ULL 2ULL 3ULL
Why does that not print '3ULL 3ULL 3ULL', if buf[0] is a reference cdata?
Thanks,
Peter
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