Search results
Results from the WOW.Com Content Network
computes the difference in seconds between two time_t values time: returns the current time of the system as a time_t value, number of seconds, (which is usually time since an epoch, typically the Unix epoch). The value of the epoch is operating system dependent; 1900 and 1970 are often used. See RFC 868. clock
Starting with Visual C++ 2005, the CRT uses a 64-bit time_t unless the _USE_32BIT_TIME_T preprocessor macro is defined. [36] However, the Windows API itself is unaffected by the year 2038 bug, as Windows internally tracks time as the number of 100-nanosecond intervals since 1 January 1601 in a 64-bit signed integer, which will not overflow ...
The Arduino platform provides relative time via the millis() function. This function returns an unsigned 32-bit integer representing "milliseconds since startup", which will roll over every 49 days. By default, this is the only timing source available in the platform and programs need to take special care to handle rollovers. [98]
The resolution of an implementation's measurement of time does not imply the same precision of such measurements. For example, a system might return the current time as a value measured in microseconds, but actually be capable of discerning individual clock ticks with a frequency of only 100 Hz (10 ms).
Real-time programs must guarantee response within specified time constraints, often referred to as "deadlines". [2] The term "real-time" is also used in simulation to mean that the simulation's clock runs at the same speed as a real clock. Real-time responses are often understood to be in the order of milliseconds, and sometimes microseconds.
Software timekeeping systems vary widely in the resolution of time measurement; some systems may use time units as large as a day, while others may use nanoseconds.For example, for an epoch date of midnight UTC (00:00) on 1 January 1900, and a time unit of a second, the time of the midnight (24:00) between 1 January 1900 and 2 January 1900 is represented by the number 86400, the number of ...
10 −3: millisecond: ms One thousandth of one second 1 ms: The time for a neuron in the human brain to fire one impulse and return to rest [13] 4–8 ms: The typical seek time for a computer hard disk: 10 −2: centisecond cs One hundredth of one second 1.6667 cs: The period of a frame at a frame rate of 60 Hz.
NTP can usually maintain time to within tens of milliseconds over the public Internet, and can achieve better than one millisecond accuracy in local area networks under ideal conditions. Asymmetric routes and network congestion can cause errors of 100 ms or more. [2] [3]