Environment: Cloud9 Ubuntu 14.04. Luajit 2.1.0-beta2Code below shows you can
pass either struct pointer or struct as second parameter of `ffi.C.gmtime_r`.
So, is this a bug? which way should I take?
```
local ffi = require("ffi")
ffi.cdef[[
typedef uint32_t time_t;
struct tm {
int second; /* Seconds. [0-60] (1 leap second) */
int minute; /* Minutes. [0-59] */
int hour; /* Hours. [0-23] */
int day; /* Day. [1-31] */
int month; /* Month. [0-11] */
int year; /* Year - 1900. */
int wday; /* Day of week. [0-6] */
int yday; /* Days in year.[0-365] */
int isdst; /* DST. [-1/0/1]*/
long int gmtoff; /* Seconds east of UTC. */
const char* zone; /* Timezone abbreviation. */
};
struct tm* gmtime_r (const time_t*, struct tm*);
struct tm* localtime_r(const time_t*, struct tm*);
char* asctime_r (const struct tm*, char*);
time_t mktime (struct tm*);
]]
local function strfmt(tm)
return string.format('%d-%s-%s %s:%s:%s',
tm.year+1900,
tm.month+1,
tm.day,
tm.hour,
tm.minute,
tm.second)
end
local seconds = 1474728477
local seconds_ptr = ffi.new("time_t[1]", seconds)
-- pass as struct
local tm = ffi.new("struct tm")
ffi.C.gmtime_r(seconds_ptr, tm)
print(strfmt(tm))
-- pass as struct pointer
local tm_ptr = ffi.new("struct tm[1]")
ffi.C.gmtime_r(seconds_ptr, tm_ptr)
print(strfmt(tm_ptr[0]))
```
Will get:
```
pronan:~/workspace (master) $ luajit test.lua
2016-9-24 14:47:57
2016-9-24 14:47:57
```
