I searched in linux box and saw it being typedef to
typedef __time_t time_t;
The time_t Wikipedia article article sheds some light on this. The bottom line is that the type of
time_t is not guaranteed in the C specification.
time_tdatatype is a data type in the ISO C library defined for storing system time values. Such values are returned from the standard
time()library function. This type is a typedef defined in the standard header. ISO C defines time_t as an arithmetic type, but does not specify any particular type, range, resolution, or encoding for it. Also unspecified are the meanings of arithmetic operations applied to time values.
Unix and POSIX-compliant systems implement the
time_ttype as a
signed integer(typically 32 or 64 bits wide) which represents the number of seconds since the start of the Unix epoch: midnight UTC of January 1, 1970 (not counting leap seconds). Some systems correctly handle negative time values, while others do not. Systems using a 32-bit
time_ttype are susceptible to the Year 2038 problem.