std:: timespec_get

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Defined in header <ctime>
int timespec_get ( std:: timespec * ts, int base ) ;
(1) (since C++17)
#define TIME_UTC /* implementation-defined */
(2) (since C++17)
1) Modifies the std::timespec object pointed to by ts to hold the current calendar time in the time base base .
2) Expands to a value suitable for use as the base argument of std::timespec_get .

Other macro constants beginning with TIME_ may be provided by the implementation to indicate additional time bases.

If base is TIME_UTC , then

  • ts - > tv_sec is set to the number of seconds since an implementation defined epoch, truncated to a whole value,
  • ts - > tv_nsec member is set to the integral number of nanoseconds, rounded to the resolution of the system clock.

Parameters

ts - pointer to an object of type std::timespec
base - TIME_UTC or another nonzero integer value indicating the time base

Return value

The value of base if successful, zero otherwise.

Notes

The POSIX function clock_gettime(CLOCK_REALTIME, ts) may also be used to populate a std::timespec with the time since the Epoch.

Example

Run this code 
#include <ctime>
#include <iostream>
 
int main()
{
    std::timespec ts;
    std::timespec_get(&ts, TIME_UTC);
    char buf[100];
    std::strftime(buf, sizeof buf, "%D %T", std::gmtime(&ts.tv_sec));
    std::cout << "Current time: " << buf << '.' << ts.tv_nsec << " UTC\n";
}

Possible output: 

Current time: 06/24/16 20:07:42.949494132 UTC

See also

(C++17)
time in seconds and nanoseconds
(struct)
returns the current time of the system as time since epoch
(function)
C documentation for timespec_get
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