How to convert NSDate into unix timestamp iphone sdk?
I believe this is the NSDate's selector you're looking for:
- (NSTimeInterval)timeIntervalSince1970
A Unix timestamp is the number of seconds since 00:00:00 UTC January 1, 1970. It's represented by the type time_t, which is usually a signed 32-bit integer type (long or int).
iOS provides -(NSTimeInterval)timeIntervalSince1970 for NSDate objects which returns the number of seconds since 00:00:00 GMT January 1, 1970. NSTimeInterval is a double floating point type so you get the seconds and fractions of a second.
Since they both have the same reference (midnight 1Jan1970 UTC) and are both in seconds the conversion is easy, convert the NSTimeInterval to a time_t, rounding or truncating depending on your needs:
time_t unixTime = (time_t) [[NSDate date] timeIntervalSince1970];
You can create a unix timestamp date from a date this way:
NSTimeInterval timestamp = [[NSDate date] timeIntervalSince1970];