Use of <time.h> in Objective-C code

Reports an include of <time.h> or a call to its clock, conversion and formatting functions from Objective-C code.

The C time API is unspecified in exactly the places an application depends on. The epoch, the resolution and the encoding of time_t and clock_t are all implementation-defined, and asctime, ctime, gmtime and localtime return a pointer into a single shared static buffer, so two calls from different threads - or even two calls in one expression - overwrite each other. None of it is calendar-aware: it has no notion of the user’s locale, of a time-zone database update, or of the twenty-four-hour setting, so dates formatted this way are wrong for part of the audience.

The following code illustrates the pattern detected by this rule:

Use the Foundation date types, which are thread safe, locale and calendar aware, and follow the user’s settings - NSDate and NSTimeInterval for instants and durations, NSCalendar/NSDateComponents for calendar arithmetic, and NSDateFormatter (or NSISO8601DateFormatter for machine-readable output) for formatting and parsing. For monotonic elapsed time use [[NSProcessInfo processInfo] systemUptime] or mach_absolute_time.

This detector does not need any configuration.